Dissertations / Theses: 'Hydrogen on Iron'

1

Nuttall, Robert Horan. "Aqueous hydrogen sulphide corrosion of iron, iron/chromium and iron/nickel alloys." Thesis, Robert Gordon University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358471.

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Nadler, Jason Hayes. "The hydrogen reduction of iron and chromium oxides." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/19410.

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3

Johnson, Tarn C. "Iron and ruthenium catalysts for hydrogen transfer reactions." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/50062/.

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The ruthenium catalysed oxidation of 1-phenylethanol derivatives with the release of hydrogen gas has been studied. A hydrogen acceptor was introduced in an effort to elucidate the rate-determining step of the reaction. The transfer of hydrogen from complex alcohols to simple aldehydes and ketones was pursued as a process for obtaining simple alcohols for fuel cell applications. The Shvo catalyst was identified as being the most efficient catalyst for the oxidation of difficult substrates. A family of iron analogues of the Shvo catalyst were synthesised and studied as precatalysts for the oxidation of alcohols. Catalyst activation was achieved by the removal of a CO ligand using trimethylamine-N-oxide and the oxidation of 1-phenylethanol derivatives with acetone was studied. Simple aldehydes were evaluated as hydrogen acceptors and a novel formylation reaction was discovered. Asymmetric iron analogues of the Shvo catalyst were synthesised and applied to the asymmetric transfer hydrogenation of acetophenone using 5:2 formic acid/triethylamine. The synthesis of further analogues with a tethering group was investigated to improve catalyst stability and enantioselectivity. Novel chiral diamine and amino-alcohol ligands containing 1,2,3-triazole functionalities were developed as ligands for the asymmetric transfer hydrogenation of ketones. Tridentate diaminotriazoles provided the best activity and selectivity in the reduction reactions with Ru3(CO)12.

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Cisloiu, Roxana. "Computational modeling of hydrogen embrittlement of iron aluminides." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1910.

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Thesis (M.S.)--West Virginia University, 2001. Title from document title page. Document formatted into pages; contains vii, 93 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71-75).

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5

BAI, XISHAN. "(CYCLOPENTADIENONE)IRON COMPLEXES IN REACTIONS INVOLVING HYDROGEN TRANSFER." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/695447.

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The PhD project focused on the synthesis and catalytic applications of (cyclopentadienone)iron complexes in reactions involving hydrogen transfer. The manuscript is divided into five chapters, and after a rather comprehensive review on the state of the art in chapter 1, the thesis describes, in the remaining four chapters, the original achievements of the PhD candidate. In particular, chapter 2 describes the applications of highly active [bis(hexamethylene)cyclopentadienone]iron tricarbonyl pre-catalyst for the reduction of imine bonds under transfer hydrogenation conditions and for the reductive amination of carbonyl compounds. In chapter 3, the application of the above mentioned pre-catalyst to alcohol amination reactions via a hydrogen borrowing mechanism is discussed. Chapter 4 deals with enantioselective ketone hydrogenations using chiral (cyclopentadienone)iron complexes containing a stereogenic plane (prepared in racemic form and resolved by chiral HPLC), and with the synthesis of chiral macrocyclic (cyclopentadienone)iron complexes, putatively more suited for the transfer of the chiral information from the catalyst to the substrate. Finally, Chapter 5 describes the immobilization of (cyclopentadienone)iron complexes into a solid support, namely Metal Organic Frameworks (MOFs), to realize an active heterogeneous (cyclopentadienone)iron catalyst for catalyst recycling in batch hydrogenation reactions and potential applications in flow processes.

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6

Liu, Simin. "Photocatalytic hydrogen production with iron oxide under solar irradiation." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/43666/1/Simin_Liu_Thesis.pdf.

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As solar hydrogen is a sustainable and environmental friendly energy carrier, it is considered to take the place of fossil fuels in the near future. Solar hydrogen can be generated by splitting of water under solar light illumination. In this study, the use of nanostructured hematite thin-film electrodes in photocatalytic water splitting was investigated. Hematite (á-Fe2O3) has a narrow band-gap of 2.2 eV, which is able to utilise approximately 40% of solar radiation. However, poor photoelectrochemical performance is observed for hematite due to low electrical conductivity and a high rate of electron-hole recombination. An extensive review of useful measures taken to overcoming the disadvantages of hematite so as to enhance its performance was presented including thin-film structure, nanostructuring, doping, etc. Since semiconductoring materials which exhibit an inverse opal structure are expected to have a high surface-volume ratio, unique optical characteristics and a shorter distance for photogenerated holes to travel to the electrode/electrolyte interface, inverse opals of hematite thin films deposited on FTO glass substrate were successfully prepared by doctor blading using PMMA as a template. However, due to the poor adhesion of the films, an acidic medium (i.e., 2 M HCl) was employed to significantly enhance the adhesion of the films, which completely destroyed the inverse opal structure. Therefore, undoped, Ti and Zn-doped hematite thin films deposied on FTO glass substrate without an inverse opal structure were prepared by doctor blading and spray pyrolysis and characterised using SEM, EDX, XRD, TGA, UV-Vis spectroscopy and photoelectrochemical measurements. Regarding the doped hematite thin films prepared by doctor blading, the photoelectrochemical activity of the hematite photoelectrodes was improved by incorporation of Ti, most likely owing to the increased electrical conductivity of the films, the stabilisation of oxygen vacancies by Ti4+ ions and the increased electric field of the space charge layer. A highest photoresponse was recorded in case of 2.5 at.% Ti which seemed to be an optimal concentration. The effect of doping content, thickness, and calcination temperature on the performance of the Ti-doped photoelectrodes was investigated. Also, the photoactivity of the 2.5 at.% Ti-doped samples was examined in two different types of electrochemical cells. Zn doping did not enhance the photoactivity of the hematite thin films though Zn seemed to enhance the hole transport due to the slow hole mobility of hematite which could not be overcome by the enhancement. The poor performance was also obtained for the Ti-doped samples prepared by spray pyrolysis, which appeared to be a result of introduction of impurities from the metallic parts of the spray gun in an acidic medium. Further characterisation of the thin-film electrodes is required to explain the mechanism by which enhanced performance was obtained for Ti-doped electrodes (doctor blading) and poor photoactivity for Zn and Ti-doped samples which were synthesised by doctor blading and spray pyrolysis, respectively. Ti-doped hematite thin films will be synthesised in another way, such as dip coating so as to maintain an inverse opal structure as well as well adhesion. Also, a comparative study of the films will be carried out.

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7

Kwan, Wai P. (Wai Pang) 1974. "Decomposition of hydrogen peroxide and organic compounds in the presence of iron and iron oxides." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29585.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003. Includes bibliographical references. Most advanced oxidation processes use the hydroxyl radical (OH) to treat pollutants found in wastewater and contaminated aquifers because OH reacts with numerous compounds at near diffusion-limited rates. OH can be made by reacting hydrogen peroxide (H202) with either Fe(II) (the Fenton reaction), Fe(1), or iron oxide. This dissertation investigated the factors that influence the decomposition rates of H202 and organic compounds, as well as the generation rate of -OH (VoH), in the presence of dissolved Fe(IH) and iron oxide. The Fe(III)-initiated chain reaction could be the dominant mechanism for the decomposition of H202 and organic compounds. The degradation rates of H14COOH, an OH probe, and H202 were measured in experiments at pH 4 containing either dissolved Fe(III) or ferrihydrite. Combined with the results from experiments using a radical chain terminator, we concluded that a solution chain reaction was important only in the Fe(III) system. In the ferrihydrite system the amount of dissolved Fe was insufficient to effectively propagate the chain reaction. In addition, a nonradical producing H202 loss pathway exists at the oxide surface. The oxidation rate of any dissolved organic compound can be predicted from VOH if the main sinks of -OH in the solution are known. Experiments using H14COOH and ferrihydrite, goethite, or hematite showed that VOH was proportional to the product of the concentrations of surface area and H202. Based on these results, a model was created for predicting the pseudo-first-order oxidation rate coefficients of dissolved organic compounds (korg) in systems containing iron oxide and H202. While our model successfully predicted korg in aquifer sand experiments, it yielded mixed results when compared to measurements from previously published studies. (cont.) Some factors that could have caused the disagreements between model predictions and measurements were examined to refine our model. Results from experiments containing goethite, H 4COOH, and 2-Chlorophenol showed that H 4COOH detected more OH, which is produced at the oxide surface, than did 2-Chlorophenol. This was attributed to electrostatic attraction between the formate anions and the positively charged oxide surface, and could explain why our model, based on H14COOH, overpredicted the korg values of many neutral compounds. by Wai P. Kwan. Ph.D.

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8

Grzeskiewicz, Ronald. "Effect of hydrogen on the coefficient of friction of iron." Thesis, This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-04122010-083727/.

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9

Jafari, A. H. "The effect of hydrogen on the passivation process of iron." Thesis, London Metropolitan University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278931.

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Pousette, Hedda. "Investigation into Melting Characteristics of Hydrogen-Reduced Iron Ore Pellets." Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-255856.

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What kinetic and thermodynamic characteristics are established in a melt of hydrogen-reduced iron ore pellets? The pellets contain self-fluxing slag components which upon melting form an initial slag. Refining capabilities of this slag, such as dephosphorization power, are investigated in a lab-scale vertical furnace. Understanding the initial slag and the reactions taking place when hydrogen-reduced iron ore pellets melt is important for future optimization of ingoing raw materials as well as industry scale process design. A sample of either crushed hydrogen-reduced iron ore pellets or a powder mixture representative of iron ore pellets in terms of composition was melted in a lab-scale vertical furnace. The sample was lowered into the argon atmosphere furnace which had a temperature of 1600°. The sample was kept inside a magnesia crucible with a molybdenum loosely-fitted lid. The purpose of the lid was to fix the oxygen partial pressure. The reduction degree of the pellets or corresponding powder mixture as well as the total melting times were varied. XRF and OES analysis were employed to find the composition of the slag and metal phases, respectively. SEM analysis was employed to investigate phases present in the slag. Comparison of melted iron ore pellets and corresponding powder mixture show that powder can be employed to represent reduced iron ore pellets accurately. It was found that reduction degree strongly impacts both phosphorus and vanadium distributions as well as the types of phases formed in the slag fraction. During melting, almost all of the Vanadium and most of the Phosphorus content goes to the slag fraction. At lower reduction degrees, dephosphorization is greater; however, the Phosphorus content in the steel is still quite high at 130 ppm or higher. Modification to the amount and/or composition of the self-fluxing slag is suggested to reach lower levels of phosphorus in the steel. Vilka kinetiska och termodynamiska egenskaper skapas i en smälta av vätgasreducerade järnmalmspellets? Pellets innehåller självflussande slaggkomponenter som vid smältning bildar en initial slagg. Slaggens raffineringsförmåga, till exempel fosforreningsförmåga, undersöks i laboratorieskala. För framtida optimering av ingående råvaror såväl som industriellskalig processdesign är det viktigt att förstå den initiala slaggen samt de reaktioner som äger rum vid nedsmältning av vätgasreducerade järnmalmspellets. Ett prov av antingen krossade vätgasreducerade järnmalmspellets eller en pulverblandning som är representativ för järnmalmspellets med avseende på sammansättning smältes ned i en laboratorieskalig vertikal ugn. Ugnen hade en argonatmosfär och temperatur på 1600°C då provet sänktes ner i ugnen för smältning. En magnesiumoxiddegel med ett löst inpassat molybdenlock användes som behållare för provet under nedsmältningen. Syftet med locket var att kontrollera syrgaspartialtrycket. Reduktionsgraden av pellets eller motsvarande pulverblandning såväl som de totala smältningstiderna varierades. XRF och OES mätverktyg användes för att undersöka sammansättning av slagg- och metallfraktionerna. SEM analys användes för att identifiera närvarande faser i slaggfraktionen. Jämförelse av nedsmälta vätgasreducerade järnmalmspellets med motsvarande pulverblandning visar att de två är representativa av varandra till stor grad. Resultaten visar på att reduktionsgraden påverkar starkt både fosfor- och vanadinfördelningarna samt faserna som bildas i slaggfraktionen. Vid smältning går nästan all mängd vanadin och majoriteten av fosfor till slaggfraktionen. Vid lägre reduktionsgrader är fosforreningen bättre. Fosforhalten i stålet är relativt hög och har ett värde på 130 ppm eller högre för samtliga prover. Ändring av mängden och/eller sammansättning av den självflussande slaggen rekommenderas för att nå lägre nivåer av fosfor i stålet.

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11

Wang, Jianing. "THE DIFFERENCES BETWEEN IRON AND IRON-SUBSTITUTED MANGANESE SUPEROXIDE DISMUTASE WITH RESPECT TO HYDROGEN PEROXIDE TREATMENT." UKnowledge, 2014. http://uknowledge.uky.edu/chemistry_etds/37.

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Iron-substituted manganese superoxide dismutase (Fe(Mn)SOD) was produced using an in vivo preparation method. It’s an inactive enzyme in catalyzing superoxide radical dismutation owing to the mis-incorporation of Fe in the active site evolved to use Mn. To investigate the possible toxicity of human Fe(Mn)SOD proposed by Yamakura, we studied the properties of Fe(Mn)SOD upon H2O2 treatment and compared to that of FeSOD. It’s found that the responses to H2O2 treatment were different, including the changes of optical spectra, variations of active site coordination and secondary structures. Fe3+ reduction was not observed in Fe(Mn)SOD even H2O2 is believed to oxidize proteins via highly reactive intermediates including Fe and formed via Fe2+, which is true in FeSOD. What’s more, the activities of Fe(Mn)SOD and FeSOD were totally different in the ABTS assay or Amplex Red assay. These results indicated that the mechanism of peroxidase reaction of Fe(Mn)SOD is not identical to that of FeSOD.

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12

Sim, Andrew Gregory Chemical Sciences &amp Engineering Faculty of Engineering UNSW. "Reduction-oxidation cycling of metal oxides for hydrogen production." Awarded By:University of New South Wales. Chemical Sciences & Engineering, 2010. http://handle.unsw.edu.au/1959.4/44763.

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A process for the production of clean hydrogen from methane based upon the sequential reduction and oxidation of metal oxides has been studied. The original process, based on iron oxide, suffers from significant disadvantages including deactivation by sintering and coke deposition. Improvement of the iron based system and identification and development of alternative metal oxides for hydrogen production has formed the basis of this study. The literature review outlines current methods for hydrogen production, followed by a review of the Steam-Iron Process as an improved and simpler method for clean hydrogen production. Thermodynamic assessment shows Fe3O4/FeO/Fe, WO3/WO2/W and SnO2/SnO/Sn to be the most prospective systems for the Steam-Metal Process. Experimental testing showed that Fe and W based systems were suitable for hydrogen production, but Sn based systems were unsuitable due to poor reducibility using methane. Attention was then focused on the addition of CeO2/ZrO2 promoters to Fe and W based systems in order to improve reactivity and prevent catalyst deactivation. CeO2/ZrO2 promoted Fe2O3 showed improved redox reactivity and increased stability, with formation of FeO. This aided in mitigation of sintering and introduced the possibility of prevention of coking, as catalysed by methane decomposition over fully reduced Fe metal. Although WO3 was found to be a suitable oxide, complete reduction to tungsten metal resulted in the formation of tungsten carbide and contamination of hydrogen produced. The formation of 31mol% [CeO2/ZrO2] / 69 mol% WO3 showed stabilised reduction using methane, allowing for redox cycling of the WO3-WO2 couple and preventing complete reduction to W metal. The use of the doped metal oxide showed the best performance of all the metal oxides tested, with clean hydrogen production over multiple redox cycles and high metal oxide stability. Further kinetic studies of both the reduction and oxidation reactions show reduction is chemical reaction controlled process (WO3/WO2.9 → WO2) with an apparent activation energy of 142 ?? 3 kJ/mol. Oxidation is also fitted to a chemically controlled process, with a reaction rate expression derived as: rH2 = [0.064 + (F x 0.00038)].e^(-108750/8.314xT).[PH2O]^(0.75) The apparent activation energy for oxidation was calculated as 109 ?? 1 kJ/mol.

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13

Silver, David Samuel. "The effect of hot dense hydrogen and argon in a ballistic compressor on the structure and composition of pure iron." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4139.

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An experimental study of pure iron foil exposed to a hot, dense hydrogen and argon gas mixture in a ballistic compressor yielded evidence of structural and compositional changes of the metal due to the presence of the hydrogen gas. Three iron foils have been compared, one of unexposed pure iron, another of pure iron exposed to a mixture of hydrogen and argon gas, and the third of pure iron exposed to argon alone. Exposure to these high temperature, high pressure gases took place in a ballistic compressor. Line formations were found on the surface of the iron foil exposed to both hydrogen and argon. These appeared as 'V'- or 'W'-shaped configurations, giving the appearance of a serrated edge. Such lines were not found for the other two iron foils. Characteristic peaks of energy dispersive x-ray spectra yield different surface concentrations of oxygen when each iron foil sample is compared. This concentration is much less for iron foil exposed to both hydrogen and argon gases than for the other two samples. Also a larger carbon peak was found for the former sample, when compared to the latter two. A shift in the 200 x-ray diffraction peak by one degree 29 was observed for the sample exposed to hydrogen and argon, and a 'triple' peak was observed for the 310 plane for the same iron sample.

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Siafakas, Dimitrios. "Investigation of Hydrogen and Nitrogen Content in Compacted Graphite Iron Production." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119086.

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The aim of this research, part of a wider program called SPOFIC, is to investigate how the casting procedure affects the concentration of hydrogen and nitrogen gases in Compacted Graphite Iron used for the production of truck cylinder blocks. Hydris equipment was used for the Hydrogen measurements and the Optical Emission Spectroscopy and combustion analysis methods were used for the nitrogen measurements. The experiment was performed in one of the cooperating foundries. It was found that Hydrogen content is increased during pouring of the melt into the mold but nitrogen content does not seem to be effected by the process. In both cases the gas content never exceeded the solubility limit. The results are comparable with results from similar researches regarding Gray Cast Iron. SPOFIC

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15

Chaudhuri, Mahua. "Removal of hydrogen sulfide from groundwater using ozone and iron oxide-coated sand /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422983.

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16

Mejia, Rodriguez Ma del Rosario. "Ligand effects on bioinspired iron complexes." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2504.

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The synthesis of diiron thiolate complexes was carried out using two ligands that were expected to furnish improved catalytic activity, solubility in water, and stability to the metal complexes. The water-soluble phosphine 1,3,5-triaza-7- phosphaadamantane, PTA, coordinates to the Fe centers forming the disubstituted complex (m-pdt)[Fe(CO)2PTA]2, which presents one PTA in each iron in a transoid arrangement. Substitution of one CO ligand in the (m-pdt)[Fe(CO)3]2 parent complex forms the asymmetric (m-pdt)[Fe(CO)3][Fe(CO)2PTA]. Enhanced water solubility was achieved through reactions with electrophiles, H+ and CH3 +, which reacted with the N on the PTA ligand forming the protonated and methylated derivatives, respectively. The 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), IMes, was reacted with (m-pdt)[Fe(CO)3]2 yielding the asymmetric (m-pdt)[Fe(CO)3][Fe(CO)2IMes], an electron rich, air stable complex that does not show reactivity with H+. Electrocatalytic production of hydrogen was studied for the all-CO, bis-PMe3, mono- and di-PTA FeIFeI complexes, as well as the PTA-protonated and -methylated derivatives. The all-CO species produce H2, in the presence of the weak HOAc, at their second reduction event, FeIFe0 ?? Fe0Fe0, that occurs at ca. ??1.9 V, through an EECC mechanism. The mono- and di-substituted phosphine complexes present electrocatalytic production of H2 from the Fe0FeI redox state; this reduction takes place at ??1.54 V for (m-pdt)[Fe(CO)3][Fe(CO)2PTA], and at ca. ??1.8 for the disubstituted PMe3 and PTA derivatives. A positive charge on the starting complex does not have an effect on the production of H2. It was found that the protonated and methylated derivatives are not the catalytic species for H2 production. At their first reduction event the neutral precursor forms, and catalysis occurs from the FeIFeI complex in all cases. The possibility of enhanced catalytic activity in the presence of H2 O was explored by conducting electrochemical experiments in the mixed CH3CN:H2O solvent system for the PTA-substituted complexes. The reduction potential of the catalytic peak is shifted to more positive values by the presence of H2 O. The cyclic voltammogram of {(m-pdt)[Fe(CO)2(PTA?? H)]2}2+ in CH3CN:H2O 3:1 shows the reduction of a more easily reduced species in the return scan. This curve-crossing event provides evidence for the (h2-H2)FeII intermediate proposed in the ECCE mechanism.

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Lei, Yun School of Chemical Engineering &amp Industrial Chemistry UNSW. "Novel Fe2O3-Cr2O3 catalyst for high temperature water gas shift reaction." Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2005. http://handle.unsw.edu.au/1959.4/23321.

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The thesis is focused on the study of high temperature water gas shift catalysis, the identification of new improved catalysts and the study of the kinetics and mechanism of reaction over these catalysts. Rh-promoted Fe2O3-Cr2O3 was found to offer best performance which was significantly better than unpromoted catalyst over wide temperatures range. An extensive literature survey is first reported. Guidelines to develop new WGS catalysts are developed. As a result, the activities of precious metals supported on various oxides for high temperature WGS reaction have been tested. Rh(1wt%) doped Fe2O3/Cr2O3, exhibits the highest activity for WGS over a wide temperature range. 5wt%CuO/Fe2O3-Cr2O3, 1wt%Pt/Cr2O3, 1wt%Pt/Fe2O3-Cr2O3, 1wt%Pt/U3O8, 1wt%Pt/10%U3O8-Al2O3 and 1wt%Pt/5%V2O5-TiO2 fall into the second most active catalysts group, with an improved activity compared to commercial Fe2O3-Cr2O3 catalyst. It is clear that both the support/catalyst and the promoter can affect the efficiency of the WGS, leading to the obvious inference that the reaction rate is controlled at the promoter ??? support interface. Further kinetic studies and characterisation (TPR, TPD, pulse-adsorption (reaction)) on Rh/Fe3O4/Cr2O3 have been conducted. The study, conducted under conditions without inhibition from products of both forward and backward reactions, shows that the overall reaction rate expression is described as: 2 22 ??? =0.0041exp(???4042.6 ) 0.64 0.5 ???0.024 exp(???6022.9 ) 0.46 0.73 CO CO H O CO H r PP P P T T . Kinetics studies carried out under fuel reforming gas compositions shows that reaction rate expression changed when the temperature of reaction varied. The reaction rate equations at temperatures of 573K, 623K and 673K are derived as: 573K: 2 2 2 - 2.84 10-6 0.6 0.12 - 9.08 10-7 0.09 0.52 rCO = ?? PCO PH O ?? PCO PH 623K: 2 2 2 - 1.45 10-6 0.99 0.40 - 7.12 10-7 0.11 0.73 rCO = ?? PCO PH O ?? PCO PH 673K: -6 2 2 2 - = 4.37 ?? 10 0.86 0.41 -1.83 ??10-6 0.28 0.66 rCO PCO PH O PCO PH , The apparent activation energy was 61.7??2.5 kJmol-1 . TPR, TPD, TPO characterisation studies and reoxidation of catalysts by CO2 or H2O show that the active site for high temperature WGS reaction on Rh/Fe2O3/Cr2O3 is reduced magnetite Fe3O4 which dissociatively breaks down the H2O to form H* and OH* and adsorbs CO2. The deposited metal, Rh, acts as a promoter by facilitating the uptake of hydrogen (H2) and carbon monoxide (CO), desorption of H2 (at high temperature) and CO2.

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18

Milne, Angela. "Marine biogeochemistry studies of iron and hydrogen peroxide using flow injection-chemiluminescence." Thesis, University of Plymouth, 2007. http://hdl.handle.net/10026.1/2007.

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Iron is an essential micronutrient for the growth of planktonic species. It is an integral element of numerous enzymes and proteins with important functions in photosynthesis and respiratory electron transport. In contrast to iron, hydrogen peroxide (H202) is ubiquitous in seawater. Phytoplankton are known to generate reactive oxygen species (ROS) such as superoxide and H202 . This production, in conjunction with membrane bound reductases, may affect an organism's ability to access nutrients such as iron. The work presented in this thesis describes the development and optimisation of sensitive flow injection-chemiluminescence techniques to assess redox processes at the cellular level and their application to investigate marine processes. Two flow injection methods, one based on direct sample injection and another involving the preconcentration of iron, were used to determine iron (II) and dissolved iron and assess potential interference from a number of metals and H202. The results demonstrated the increased oxidation of Fe(II) in the presence of H202 (half life reduced from 10.4 to 3.5 min at 50 nM H202) and confirmed the ability of the pre-concentration method to remove this matrix interference. The accuracy and precision of the pre-concentration method were confirmed through analysis of samples collected on two international intercomparison studies. The results demonstrated that the method was precise (- 8 %RSD) and provided a suitably low limit of detection (17 pM) for the determination of dissolved iron. Dust deposition is an important source of iron to remote open ocean regions. The solubility of iron and aluminium in North Atlantic waters was assessed through an on-deck dissolution experiment. Calculated solubilities of iron released from six differing dust samples were low and varied from 0.001 to 0.04 %, whereas the release of aluminium ranged from 0.06-9.0 %. Solubility was inversely correlated with particle concentration, where higher solubility was observed for lower particle concentrations. A versatile and adaptable FI system was developed, with a low detection limit (0.4 - 1.3 nM), excellent precision (1.1-1.8 %RSD) and the capability of sensitive real-time determination of H202 over a wide dynamic range. The results from laboratory based assays using a novel in-line filter approach demonstrated H202 production by the diatom species Thalassiaira ueiss weissflogii with observed concentrations in the range 30- 100 nM. In addition, through field studies carried out in two different oceanic regions (English Channel and Ross Sea), a previously unreported correlation between phytoplankton biomass and surface H20 1 concentrations was observed. The FI-CL instrumentation for the determination of Fe(II) was successfully adapted and optimised for the continuous in-line measurements of Fe(II) generated by diatoms. This technique provided a low detection limit (11 pM) and excellent precision (6.3 ± 3.2 % RSD). In further laboratory based assays with T. ueissflogii, preliminary results indicated pM changes in Fe(II) generation following the reduction of organically bound Fe(Ill).

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19

Zhang, Wanji. "Dye-Sensitized Tio2 Modified with Iron Polypyridyl Catalyst for Photocatalytic Hydrogen Evolution." W&M ScholarWorks, 2016. https://scholarworks.wm.edu/etd/1477068478.

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Artificial Photosynthesis (AP) focuses on finding a way to harness solar energy to generate a chemical fuel. TiO2 semiconductors are of interest to AP research due to its relatively low cost and widespread use as an efficient charge-separating support. This research focuses on the development of a device for photocatalytic hydrogen generation. Our approach utilizes the immobilization of iron polypyridyl catalysts and ruthenium chromophores on TiO2 through stable phosphonic acid anchoring groups.

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20

Lee, Changmin. "Effect of various dissolved species on anaerobic iron corrosion." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/43875.

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Iron corrosion is an extremely complicated process because numerous factors such as pH, DO, temperature, inhibitor, and other various constituents in water can exert a controlling influence. The economic importance of problems that are caused by corrosion has been recognized. Therefore, the necessity of better understanding corrosion phenomenon is apparent. The effect of phosphorus, especially in oxidation states different than phosphate (+V) (e.g., PO3-3, PO2-3 and PH3 gas), on anaerobic iron corrosion was examined. Tests were conducted at pH 3, 7, and 10- 11 in a solution of 10-3 M NaCl. There was not a significant catalytic effect of phosphorus species on anaerobic iron corrosion. Higher levels of PH3 did markedly increase H2 evolution, consistent with observations of other researchers, but it is possibly due to oxidation of PH3 by iron surfaces with production of H2. Various constituents were also tested for iron corrosion in anaerobic solution [Al3+ (soluble), Al(OH)3, Cu2+, Si(OH)4, Boron, NOM, and sulfide] at pH pH 3, 7, and 10-11. None of these appeared to inhibit corrosion compared to a control. At pH 7, soluble Al3+ and Cu2+ in solution led to much higher production of H2 relative to a control. Phosphorus species had little impact on iron corrosion rates in the presence of sulfides (198 mg/L as S2-). In much of the research, recovery of H2 in the headspace was much lower than was predicated based on classic equations. This implies that some other, and as yet unappreciated, reactions are occurring in this system. However, in other instances the recovery of hydrogen was consistent with classical theory. Future work should examine the circumstances in which agreements and disagreements with classic theory occur. Master of Science

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Mader, Elizabeth Anne. "Hydrogen atom transfer reactions of iron and cobalt tris alpha-diimines : a study of intrinsic and thermodynamic effects /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/8617.

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Ansaloni, Simone. "Oxidative properties of the Iron - Thymine-1-acetic acid - Hydrogen peroxide catalytic system." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4937/.

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The oxidation of alcohols and olefins is a pivotal reaction in organic synthesis. However, traditional oxidants are toxic and they often release a considerable amounts of by-products. Here, two IronIII-based systems are shown as oxidative catalyst, working in mild conditions with hydrogen peroxide as primary oxidant. An efficient catalytic system for the selective oxidation of several alcohols to their corresponding aldehydes and ketones was developed and characterized, [Fe(phen)2Cl2]NO3 (phen=1,10-Phenantroline). It was demonstrated that the adoption of a buffered aqueous solution is of crucial importance to ensure both considerable activity and selectivity.The Iron - Thymine-1-acetic acid in-situ complex was studied as catalyst in alcohol oxidations and C-H oxidative functionalization, involving hydrogen peroxide as primary oxidant in mild reaction conditions. The catalytic ability in alcohol oxidations was investigated by Density Functional Theory calculations, however the catalyst still has uncertain structure. The system shows satisfactory activity in alcohol oxidation and aliphatic rings functionalization. The Fe-THA system was studied in cyclohexene oxidation and oxidative halogenations. Halide salts such as NBu4X and NH4X were introduced in the catalytic system as halogens source to obtain cyclohexene derivatives such as halohydrins, important synthetic intermediates.The purpose of this dissertation is to contribute in testing new catalytic systems for alcohol oxidations and C-H functionalization. In particular, most of the efforts in this work focus on studying the Iron - Thymine-1-acetic acid (THA) systems as non-heme oxidative model, which present: •an iron metal centre(s) as a coordinative active site, •hydrogen peroxide as a primary oxidant, •THA as an eco-friendly, biocompatible, low cost coordinating ligand.

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Cussó, Forest Olaf. "Highly enantioselective epoxidation with hydrogen peroxide and biologically inspired iron and manganese catalysts." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/393903.

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Asymmetric epoxidation is one of the most important reactions in synthetic organic chemistry, because chiral epoxides act as versatile electrophiles which can be converted in a number of interesting and useful chiral products. It’s known that current methodologies for obtaining excellent enantioselectivities need to be improved in terms of reaction times, use of not expensive or toxic metals, and avoidance of chlorinated solvents and oxidants that produce undesired wastes. Natural systems, such as iron enzymes are capable of perform this chemistry with high selectivity and efficiency under very mild conditions. Inspired by oxidations taking place at oxygenases, the combination of iron- and manganese-based catalysts and hydrogen peroxide is an attractive approach for developing oxidation methods because of availability, low cost and low toxicity considerations. One of the main objectives of this thesis is the development of iron and manganese complexes that mimics the structure and functions of these natural enzymes and the finding of new methodologies for enantioselective epoxidations using environmentally not aggressive conditions. One of the strategies developed in this thesis consists in investigating iron and manganese chiral coordination complexes with different electronic and steric properties on the ligand. Furthermore, it was envisioned that the study of these compounds could give useful information about the oxidation mechanism operating in oxygenase enzymes and may help to provide a basis for a rational design for future catalyst developments. The results obtained in this thesis show that the electronic properties of the ligand play an important role in order to get excellent enantioselectivities and different carboxylic acid additives can extent the substrate scope of the system. Finally, three new iron and manganese complexes are described as an efficient and stereoselective catalysts capable of performing highly enantioselective epoxidation of different kind of olefins, such as, cis-aromatic, trans-aromatic and also challenging substrates such as steroids, cyclic aliphatic enones and terminals olefins. L’epoxidació asimètrica és una de les reaccions més importants de la química orgànica. Perquè els epòxids quirals actuen com a electròfils versàtils, els quals poden ser convertits en productes quirals interessants i útils. És conegut que les metodologies actuals per obtenir altes enantioselectivitats necessiten ser millorades en termes de temps de reacció, l’ús de metalls tòxics i cars, i evitar dissolvents clorats i oxidants que produeixen subproductes no desitjats. Els sistemes natural, com els enzims de ferro, són capaços de dur a terme aquesta química amb altes selectivitats i eficiències sota condicions suaus. Inspirat en les oxidacions que tenen lloc en les oxigenases, la combinació de catalitzadors de ferro i manganès amb aigua oxigenada és un atractiu punt de partida per desenvolupar mètodes d’oxidació, degut a la seva disponibilitat, baix cost i baixa toxicitat. Un dels principals objectius d’aquesta tesis és el desenvolupament de catalitzadors de ferro i manganès que imiten l’estructura i les funcions dels enzims naturals i trobar una nova metodologia per fer epoxidacions enantioselectives utilitzant condicions no agressives. Una de les estratègies desenvolupades en aquesta tesis consisteix en investigar complexos de coordinació de ferro i manganès amb diferents propietats electròniques i estèriques en el lligand. A més, es preveu que els estudis d’aquests compostos podria donar informació útil sobre els mecanismes d’oxidació que operen en les oxigenases i també podria aportar conceptes bàsics per el disseny de futurs catalitzadors. Els resultats obtinguts en aquesta tesis mostren que les propietats electròniques dels lligands juguen un paper molt important a l’hora d’obtenir altes enantioselectivitats i l’ús de diferents àcids carboxílics pot expandir el nombre de substrats possibles a epoxidar d’aquest sistema. Finalment, tres nous complexos de ferro i manganès han esta descrits com a catalitzadors eficients i estereoselectiius capaços de dur a terme epoxidacions altament enantioselectives de diferents tipus d’olefines, com ara cis-olefines, trans-olefines i també substrats més difícils com ara, esteroides, enones cícliques alifàtiques i olefines terminals.

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Onyegbule, Nkele. "Composite low temperate hydrogen storage material on the basis of iron-titanium alloy." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6344_1242888003.

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It is widely believed that hydrogen will, within a few years, become the means of storing and transporting energy. The reason is the depletion of hydrocarbons and the relatively facile production of hydrogen from various renewable sources of energy. Hydrogen can be combusted in an efficient way in a fuel cell with water as emission product. The overall goal of the project was to deevlop the knowledge base for solid-state hydrogen storage technology suitable for stationary and mobile applications. The aim of this research was to develop a novel composite hydrogen storage material with high wt% storage capacity, high intrinsic safety, appropriate thermodynamics, high mechanical strength, reversibility of the system and fast kinetics based on a well known &quot low temperature&quot intermetallic alloy (Ti/Fe) as the core.

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Canas, Carlos Gonzalo. "Hydrogen sulfide removal from biogas with a fixed bed of rusted iron turnings." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26220.

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Biogas produced at farm level has many applications, however the hydrogen sulfide must be eliminated from the biogas to prevent any possible damage to equipment, users and operators, and the environment. Among the various options available to the farmer to clean hydrogen sulfide from biogas a fixed-bed of rusted iron turnings seems appropriate. This study investigated the effectiveness of a fixed bed of rusted iron turnings in eliminating hydrogen sulfide. For that purpose, dynamic bench scale test were done to study the effects of flow rate (0.5 l/min, 0.75 l/min and 1.0 l/min) and hydrogen sulfide concentration (100 ppm and 200 ppm). The gas used was a mixture of saturated carbon dioxide and hydrogen sulfide. The iron turnings were made with a uniform thickness and width and allowed to oxidize under atmospheric conditions for 8 weeks. The resulting breakthrough curves were well described by sigmoidal curves. The breakpoint time was affected by flow rate and hydrogen sulfide concentration. At the higher flows and concentrations the breakpoint times were smaller. In contrast, the mass of hydrogen sulfide removed up to breakpoint time was independent of flow rate and hydrogen sulfide concentration (0.83 g). Nevertheless, the maximum removal capacity was independent of hydrogen sulfide concentration but dependent on flow rate. The rate data conformed well to a surface rate model, however the calculated pseudo-rate constants were different for the flow rates and hydrogen sulfide concentrations used in this study. Thus it was not possible to define a mechanism control for the rate of reaction. The fixed-bed was able to eliminate hydrogen sulfide from the gas mixture, however only 30 to 44% of the iron oxide reacted. Applied Science, Faculty of Graduate

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Campen, Adam. "Separation of hydrogen from syngas using a regenerative iron oxide-calcium oxide system /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1240703561&sid=3&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (M.S.)--Southern Illinois University Carbondale, 2006. "Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (leaves 64-69). Also available online.

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Murugan, Arul. "Iron-containing perovskite materials for stable hydrogen production by chemical looping water splitting." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1488.

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The purpose of this thesis is to investigate „chemical looping water splitting‟ processes for hydrogen production which involves reducing a solid oxygen carrier material (such as iron oxide) by a reducing agent such as carbon monoxide, syngas or methane. Following this, a second step can be performed where water is used to oxidise the metal, thereby producing free hydrogen (without requiring any separation steps). These two steps (reduction and oxidation) can be repeated to perform redox cycles which would continuously utilise the solid oxygen carrier material. Initial experiments were performed using temperature programmed redox cycles to perform chemical looping water-gas shift and compare the performance of two perovskites (La0.6Sr0.4Co0.2Fe0.8O3-δ and La0.7Sr0.3FeO3-δ) against two supported metal oxides (60% Fe2O3/Al2O3 and 20% NiO/Al2O3). The best performing materials of the perovskites (La0.7Sr0.3FeO3-δ) and support metal oxides (60% Fe2O3/Al2O3) were further tested in isothermal chemical looping water-gas shift cycles over 150 redox cycles to assess material lifetime. The results showed that 60% Fe2O3/Al2O3 under these conditions had deactivated due to the formation of FeAl2O4 which led to lower hydrogen production. La0.7Sr0.3FeO3-δ gave high material stability and steady hydrogen production over more than 100 redox cycles. A nickel-containing perovskite La0.7Sr0.3Fe0.9Ni0.1O3-δ was synthesised and subjected to the same experimental conditions but this material showed no improvement compared to La0.7Sr0.3FeO3-δ in terms of hydrogen production, hydrogen purity and material stability. In an additional experiment 60% Fe2O3/Al2O3 and La0.7Sr0.3FeO3-δ were used as oxygen carrier materials in a three-step chemical looping process involving reduction by methane (to form syngas), water oxidation and air oxidation (to provide heat). 60% Fe2O3/Al2O3 gave good hydrogen purities during water oxidation but showed low material stability, whereas La0.7Sr0.3FeO3-δ showed no loss in material stability but gave low hydrogen purity, possibly due to carbon deposition during the reduction step.

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Yarahmadi, Sina. "Preparation and performance of nanostructured iron oxide thin films for solar hydrogen generation." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8131.

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Nowadays, energy and its resources are of prime importance at the global level. During the last few decades there have been several driving forces for the investigation of new sources of energy. Hydrogen has long been identified as one of the most promising carriers of energy. Photoelectrochemical (PEC) water splitting is one of the most promising means of producing hydrogen through a renewable source. Hematite (α-Fe2O3) is a strong candidate material as photoelectrode for PEC water splitting as it fulfils most of the selection criteria of a suitable photocatalyst material for hydrogen generation such as bandgap, chemical and photelectrochemical stability, and importantly ease of fabrication. This work has explored different preparation techniques for undoped and Si-doped iron oxide thin films using microwave-assisted and conventional preparation methods. Two distinct strategies towards improving PEC performance of hematite photoelectrodes were examined: retaining a finer nanostructure and enhancing the photocatalytic behaviour through doping. By depositing thin films using atmospheric pressure chemical vapour deposition (APCVD) and aerosol-assisted CVD (AACVD) at high temperature, it was shown that a combination of different factors (such as silicon incorporation into the hematite structure and formation of lattice defects, along with a nanostructure of small agglomerate/cluster enhancing hole transportation to the surface) were the contributing factors in improving the PEC performance in hematite films. The role of the Si-containing precursors and their consecutive effect on nanostructure of the hematite films were investigated. Further work is needed to study the decomposition pattern of precursors and consequent effects of Si additives as well as co-dopants on fundamental physical and electrical properties of hematite electrodes. In addition, the feasibility of using microwave annealing for the fabrication of iron oxide thin films prepared by electrodeposition at low temperature was also investigated. Hematite films showed improved PEC performance when microwave assisted annealing was used. Microwave heating decreased the annealing temperature by ~40% while the PEC performance was increased by two-fold. The improved performance is attributed to the lower processing temperatures and rapidity of the microwave method that help to retain the nanostructure of the thin films whilst restricting the grain coalescence to a minimum. Around 60% of the energy can be saved using this low carbon foot-print approach compared to conventional annealing procedures for the lab-scale preparation of hematite films – a trait that will have significant implications for scale-up production. The lower processing temperature requirements of the microwave process can also open up the possibility of fabricating hematite thin films on conducting, flexible, plastic electronic substrates.

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Jonas, S. K. "Hydrogen peroxide-induced cell damage : the role of free radicals and iron complexes." Thesis, Brunel University, 1988. http://bura.brunel.ac.uk/handle/2438/5395.

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This thesis presents data exploiting one of the important chemico-biological characteristics of the transition metal iron: its ability to exist in two oxidation states. Manipulation of the reactivity of iron by ligands has been reflected by the oxygen utilisation or the amount of ferrozine-detectable Fe2+. Ligand-dependent cell associated iron has been demonstrated by prussian blue staining and ferrozinedetectable iron. Iron/8-hydroxyquinoline enters the cell by diffusion, whereas iron dextran is endocytosed as is evident from extensive vesicular staining. The involvement of iron in the cytotoxicity of H202 has been examined (a) indirectly by introduction of reducing agents which restore the cytotoxicity of H202 at 4°C (an effect which is abolished by desferrioxamine) and (b) directly by extracellularly added iron, which enhances the cytotoxicity if the iron is internalised but protects the cell if the iron remains extracellular. Cytotoxicity has been estimated by plating efficiency and by a modified tritiated thymidine incorporation assay permitting a 24 hour delay before exposure to the label. Direct free radical interaction with a ligand itself is exemplified by the production of the nitroxide free radical in desferrioxamine. This causes extensive damage to yeast alcohol dehydrogenase but can be protected by ascorbate, methionine and iron/EDTA but not iron dextran. The findings lend further support for the suggestion that free radical generation by the Fenton reaction enhances the potential cytotoxic effect of H202 provided the reactions occur at critical sites within the cell.

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Hanson, John Paul Ph D. Massachusetts Institute of Technology. "The role of grain boundary character in hydrogen embrittlement of nickel-iron superalloys." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/112382.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 183-196). Hydrogen embrittlement of engineering alloys is characterized by a loss of ductility and unpredictable failure. These failures affect numerous industries, including nuclear power, oil and gas exploration, and hydrogen transportation and storage. In face-centered cubic alloys, the resultant fracture is intergranular and very sensitive to grain boundary character. We study this behavior in alloy 725, a popular nickel-iron superalloy with high strength and corrosion resistance. Using a suite of complementary experimental techniques we reveal the fracture behavior of individual grain boundaries in hydrogen embrittlement for the first time, providing critical understanding of the role of grain boundary character and informing improved microstructure design. We study crack propagation in hydrogen embrittled tensile test specimens using highenergy diffraction-microscopy, a non-destructive X-ray synchrotron technique capable of mapping grain boundaries in 3-D. We find that boundaries with low-index planes (BLIPs), defined as planes within 10° of [111], [110] or [100], resist crack propagation and improve toughness. We show that coherent twin boundaries (CTBs), a subset of BLIPs, also indirectly improve toughness by increasing the heterogeneity of the grain boundaries they intersect. In addition, we use electron backscatter diffraction and scanning electron microscopy to identify the grain boundaries along which cracks initiate and propagate on the sample surface. We unambiguously show that grain boundaries are the source of crack initiation, and we study a statistically significant number of cracking events, providing the ability to determine the role of grain boundary character. Surprisingly, we find that while CTBs resist crack propagation, they preferentially initiate cracks. These results inform a more nuanced approach to microstructure design. Typically grain boundary engineering techniques aim to maximize the fraction of low-S boundaries as designated by the coincident site lattice model. Our results suggest that these techniques should maximize the fraction of BLIPs instead. In addition, the dual nature of CTBs suggests the development of graded microstructures, with high concentrations of CTBs in the interior to resist crack propagation and reduced concentrations at the surface to limit crack initiation. by John Paul Hanson. Ph. D.

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Cleeton, Jason Paul Edward. "Chemical looping combustion with simultaneous power generation and hydrogen production using iron oxides." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609734.

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Race, Nicholas. "Iron Polypyridyl Catalysts Assembled on Metal Oxide Semiconductors for Heterogeneous Photocatalytic Hydrogen Generation." W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1530192812.

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Artificial Photosynthesis (AP) provides a promising method for the conversion of solar energy to chemical fuel in the form of H2 and O2. Development of heterogeneous systems in which H2 evolution catalysts are immobilized on metal oxide semiconductors is imperative for the large-scale implementation of AP systems. This research focuses on the immobilization of an active H2 evolution catalyst on large band gap semiconductors for the development and optimization of a highly active photocatalytic H2 generation system.

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Smith, Thomas. "Synthesis and evaluation of non-platinum catalysts for a novel hydrogen fuel cell cathode." Thesis, University of Manchester, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632332.

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Current state-of-the-art fuel cells depend on relatively high quantities of platinum metal to function. For fuel cells to become economically feasible as a replacement for the internal combustion engine there needs to be a drastic reduction in the quantity of platinum used within them. ACAL Energy has developed a fuel cell that allows for an 80 % reduction in the quantity of platinum required. This is achieved by replacing the solid supported cathode with an aqueous catholyte solution that contains within it a non-precious metal catalyst. The work contained in this thesis explores a library of non-heme metal complexes as potential candidates for use as catalysts for the 4 electron oxygen reduction reaction at the cathode of the FlowCath® fuel cell. The catalysts chosen, Fe(II) TPEN, Fe(II) TRILEN and Fe(II) TPTCN, are super oxidise dismutase mimics and are known to effectively reduce oxygen in a homogeneous solution. These catalysts were studied in fuel cell-like conditions to gain an understanding of their effectiveness in reducing oxygen. Attempts to decorate the complexes with sulfonate groups led to the evolution of the isoquinoline-based complexes. The change from pyridine-based complexes to isoquinoline-based complexes led to the formation of six alternative complexes, Fe(II) 1-miq TQEN, Fe(II) 3-miq TQEN, Fe(II) 1-miq TRILEN, Fe(II) 3-miq TRILEN, Fe(II) 1-miq TQTCN and Fe(II) 3-miq TQTCN, four of which (1-/3-miq TRILEN and 1-/3-TQTCN) are new to the academic literature. These complexes were analysed for their use as catalysts in the oxygen reduction reaction. In addition to the synthetic and analytical work carried out, computational models of the complexes were created. This theoretical data gave a deeper insight into the molecular structure of the complexes studied and the spin states of the Fe(II) and Fe(III) species.

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Hughes, Paula Jeanne. "Development and breakdown of chromia scales on iron-25 chromium alloys in hydrogen/water/hydrogen sulfide atmospheres at 700 degrees C." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1059408227.

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Alharthi, Abdulrahman. "Hydrogen and carbon nanostructure formation from methane cracking over iron and zeolite based catalysts." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5309/.

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The production of hydrogen by the catalytic cracking of methane was investigated. An extensive study was undertaken on two categories of materials, namely iron-containing wastes and prepared catalysts, which include palladium-based catalysts, nickel-based catalysts and a copper-based catalyst. Three types of iron-containing waste materials were examined as pre-catalysts. The iron waste samples comprised a biogenic sample from a local Landfill site; waste residue sample from an old local nail works site and Red Mud. The resulting waste iron catalysts are environmentally benign and may be “thrown away” following use. The biogenic sample presented an unusual tubular morphology resulting from its biogenesis. All these materials possessed significant peak activity for hydrogen production at 800 °C. Significant carbon deposition occurred on these samples. Calcination of biogenic and waste residue samples at 900 °C enhanced performance. Carbon was deposited in the form of carbon filaments on the waste residue sample. The addition of Pd promoted the biogenic sample’s activity but poisoned the waste residue sample. Cracking of methane over palladium-containing zeolite catalysts has also been studied. Pd/H-ZSM-5 exhibited the highest peak hydrogen formation rate at 750 °C and the highest amount of carbon was produced at 900 °C. The addition of Ni, Co, Cu and Fe dopants did not improve performance. The effect of support type (H-ZSM-5, -Al2O3 and SiO2) on the Pd catalyst performance was also investigated, with -Al2O3 producing the best activity. All post-reaction Pd catalysts showed the formation of carbon filaments. On comparing the catalytic activity of Pd/H-ZSM-5, Ni/H-ZSM-5 and Cu/H-ZSM-5, it was found that Pd/H-ZSM-5 catalyst possessed the highest activity, while Ni/H-ZSM-5 and Cu/H-ZSM-5 catalysts showed lower activity and similarity to each other in behaviour. Carbon filaments were formed over Pd/H-ZSM-5 and Cu/H-ZSM-5 but did not form over Ni/H-ZSM-5. It was observed that the carbon filaments only grow at higher Ni-loading on the zeolite. The catalytic activities of Ni on different supports were evaluated and SiO2 was found to be the most effective support.

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Bowen-Jones, Megan. "Iron(III) tetraamide macrocycles : synthesis and use as catalysts for oxidation with hydrogen peroxide." Thesis, University of York, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274538.

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Brown, Thomas Joseph. "The use of (cyclopentadienone)iron tricarbonyl complexes and ruthenium complexes for hydrogen transfer reactions." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/103451/.

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The synthesis of (cyclopentadienone)iron tricarbonyl complexes and the application of said complexes to the catalysis of ‘hydrogen borrowing’ reactions between amines and alcohols has been studied. A family of analogous (cyclopentadienone)iron tricarbonyl complexes were synthesised and used in ‘hydrogen borrowing’ with aniline and analogous alcohol reagents comprising increasing carbon chain length, in an attempt to gain more understanding of the effect of altering the electron environment of the hydroxy group of the active iron catalysts generated from the synthesised (cyclopentadienone)iron tricarbonyl complexes. Utilising an alternative set of reaction conditions, the scope of the ‘hydrogen borrowing’ methodology was extended to include amines derived from piperidine, benzylamine and other aliphatic amines. The incorporation of additional functionality (e.g. alkene or alkyne groups) into the product amines was also found to be an option of the new methodology. The synthesis of novel asymmetric (cyclopentadienone)iron tricarbonyl complexes was also attempted and a novel application of Ru(II)/TsDPEN hydrogen transfer catalysts was also discovered.

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Huggins, Gonzalez Angeire Sugey. "Galvanic Interactions in Sweet and Sour Environments." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1557002644383622.

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McMillan, Duncan George Glenn, and n/a. "Proton and iron capture mechanisms of Bacillus sp. strain TA2.A1 at alkaline pH values." University of Otago. Department of Microbiology & Immunology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081104.090840.

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The thermoalkaliphilic Bacillus sp. strain TA2.A1 was able to grow in pH-controlled batch culture containing a fermentable growth substrate (i.e. sucrose) from pH 7.5 to 10.0 with no significant change in specific growth rate, suggesting that this bacterium is a facultative alkaliphile. However, when strain TA2.A1 was grown on non-fermentable carbon sources like succinate, no growth was observed until the external pH was > 9.0, suggesting this bacterium is an obligate alkaliphile. Growth on succinate at pH 9.5 was sensitive to both carbonyl cyanide m-chlorophenylhydrazone (CCCP) and monensin revealing that both the proton and sodium motive force ([Delta][mu][H⁺] and [Delta][mu][Na⁺], respectively) were obligate requirements for growth at alkaline pH values. Transport of succinate was driven by a chemical gradient of Na⁺ ([Delta]pNa⁺) that was strictly coupled to [Delta][Psi]. A single transport system was detected for the uptake of succinate, with an apparent K[m] of 19 [mu]M and V[max] of 0.45 nmol succinate/min/mg protein. Succinate transport was pH-dependent, and showed optimal activity at pH values greater than 8.5. Other C₄-dicarboxylates (e.g. malate, fumarate) inhibited the uptake of succinate suggesting that the permease was general for other C₄-dicarboxylates. Cytochrome content, succinate dehydrogenase oxidoreductase, and F₁F₀-ATPase activities were lower in membranes from strain TA2.A1 cells grown at pH 7.5 compared to those cultured at 9.5. These data suggest that oxidative phosphorylation-linked processes are down-regulated at neutral pH values, an observation that mirrored oxygen consumption profiles of strain TA2.A1 in whole cells. To study this phenomenon at a molecular level, we measured ATP synthesis by the F₁F₀-ATP synthase from strain TA2.A1 as a function of pH. The strain TA2.A1 F₁F₀-ATP synthase had a pH optimum for ATP synthesis of 9.0-9.5, and significantly lower rates of ATP synthesis observed below pH 9.0. Analysis of the atp operon from the thermoalkaliphilic Bacillus sp. strain TA2.A1 and comparison with other atp operons from alkaliphilic bacteria reveals the presence of a conserved lysine residue at position 180 (Bacillus sp. strain TA2.A1 numbering) within the a subunit of these F₁F₀-ATP synthases. We hypothesize that the basic nature of this residue is ideally suited to capture protons from the bulk phase at high pH. To test this hypothesis, a heterologous expression system for the ATP synthase from Bacillus sp. TA2.A1 (TA2F₁F₀) was developed in Escherichia coli DK8 ([Delta]atp). Amino acid substitutions were made in the a subunit of TA2F₁F₀ at position 180. Lysine (aK180) was substituted for the basic residues histidine (aK180H) or arginine (aK180R), and the uncharged residue glycine (aK180G). ATP synthesis experiments were performed in ADP plus P[i]-loaded right-side out membrane vesicles energized by ascorbate-phenazine methosulfate. When these enzyme complexes were examined for their ability to perform ATP synthesis over the pH range from 7.0 to 10.0, TA2F₁F₀ and aK180R showed a similar pH profile having optimum ATP synthesis rates at pH 9.0 to 9.5 with no measurable ATP synthesis at pH 7.5. Conversely, aK180H and aK180G showed maximal ATP synthesis at pH�s 8.0 and 7.5, respectively. ATP synthesis under these conditions for all enzyme forms was sensitive to DCCD. These data strongly imply that amino acid residue K180 is a specific adaptation within the a subunit of TA2F₁F₀ to facilitate proton capture at high pH. At pH values near the pK[a] of K180, the trapped protons readily dissociate to reach the subunit c binding sites but this dissociation is impeded at neutral pH values causing either a blocking of the proposed H⁺ channel and/or mechanism of proton translocation, and hence ATP synthesis is inhibited. The mechanisms where by alkaliphilic bacteria obtain iron remains unknown. Growth of strain TA2.A1 at pH 9.5 in the presence of the artificial iron chelators ethylenediamine O-hydroxyphenylacetic acid (EDDHA) and 2�2� dipyridal revealed that iron is an important requirement for aerobic growth at alkaline pH values. Furthermore, biochemical analysis showed that Bacillus alcalophilus and Bacillus pseudofirmus both synthesized orange catecholate siderophores, whilst Bacillus halodurans synthesized a hydroxamate siderophore. These tests showed that strain TA2.A1 synthesized both orange catecholate and hydroxamate siderophore/s. Attempts to purify the catecholate were unsuccessful. No homologues of previously identified non-ribosomal peptide synthase (NRPS) genes in Bacillus subtilis and B.halodurans were detected in the genome of strain TA2.A1 using both PCR and Southern hybridization using known non-ribosomal peptide synthase genes.

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Ning, Jing. "The Role of Iron Sulfide Polymorphism in Localized Corrosion of Mild Steel." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1476660078407962.

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Chohan, Urslaan. "Modelling early stages of hydrogen embrittlement and surface oxidation of iron using density functional theory." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/modelling-early-stages-of-hydrogen-embrittlement-and-surface-oxidation-of-iron-using-density-functional-theory(52c00a91-b779-4c0a-9dc7-688916f7bf57).html.

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In this project, I have modelled the adsorption and diffusion of hydrogen and oxygen on and through the three low-index planes of two phases of iron, namely the body-centred cubic ferromagnetic alpha iron, alpha-Fe, and face-centered cubic gamma iron phase, gamma-Fe. This was done using spin-polarised Density Functional Theory, and the minimum energy path for the diffusion calculation was derived from potential energy surfaces created from a tight 3D mesh through the crystal. It was found that oxygen and hydrogen atoms strongly chemisorb on the (110) phase. Oxygen strongly chemisorbs on alpha-Fe(110) at the quasi-threefold site, with a surface stretch ~500 cm-1 for higher coverage. The structural changes at the highest coverage (>0.5 ML) indicated the incipient formation of FeO(111) from the O-Fe(110) overlay. Studying the electronic properties of the formation of FeO(111) yields an understanding of the earliest stage of oxide formation. Hydrogen was found to strongly chemisorb on the (110) surface of alpha-Fe. The hydrogen adsorbs at the quasi-threefold site with an adsorption energy of ~3 eV/H atom and surface stretches at ~1100 cm-1 for higher coverages. The (111) surface of gamma-Fe has been found to have the highest barrier for bulk-like diffusion. The bulk-diffusion barrier for hydrogen through gamma-Fe is ~0.7 eV for the (111) surface, which is ~0.2 eV higher than the (110) surface. The presence of magnetism in the (001) surface of gamma-Fe resulted in a lowering in the bulk-like diffusion barrier, with an ~0.2 eV barrier in the ferromagnetic surface as opposed to the ~0.6 eV in the non-magnetic surface. The high barrier for the (111) surface of gamma-Fe demonstrates that producing textured austenitic steel components with this surface exposed to the hydrogen source may work to lower the hydrogen damage in these samples. The strong effect of magnetism in lowering the barrier for diffusion demonstrates the importance of avoiding ferromagnetic austenitic steel alloys in environments where hydrogen is in abundance. These results may be applied in the process of development of Gen IV fission and fusion reactors. Ferritic and austenitic steels are ideal candidates for a number of components in these reactors, such as the first wall/breeding blanket. There is an abundance of presence of hydrogen in nuclear reactors. Hydrogen may enter the metallic matrix through diffusion processes, leading to the embrittlement of these components. Additionally, oxygen is readily present in the environment, which may oxidise components. In this project, I have modelled the adsorption and diffusion of hydrogen and oxygen on and through the three low-index planes of two phases of iron, namely the body-centred cubic ferromagnetic alpha iron, alpha-Fe, and face-centered cubic gamma iron phase, gamma-Fe. This was done using spin-polarised Density Functional Theory, and the minimum energy path for the diffusion calculation was derived from potential energy surfaces created from a tight 3D mesh through the crystal. It was found that oxygen and hydrogen atoms strongly chemisorb on the (110) phase. Oxygen strongly chemisorbs on alpha-Fe(110) at the quasi-threefold site, with a surface stretch ~500 cm-1 for higher coverage. The structural changes at the highest coverage (>0.5 ML) indicated the incipient formation of FeO(111) from the O-Fe(110) overlay. Studying the electronic properties of the formation of FeO(111) yields an understanding of the earliest stage of oxide formation. Hydrogen was found to strongly chemisorb on the (110) surface of alpha-Fe. The hydrogen adsorbs at the quasi-threefold site with an adsorption energy of ~3 eV/H atom and surface stretches at ~1100 cm-1 for higher coverages. The (111) surface of gamma-Fe has been found to have the highest barrier for bulk-like diffusion. The bulk-diffusion barrier for hydrogen through gamma-Fe is ~0.7 eV for the (111) surface, which is ~0.2 eV higher than the (110) surface. The presence of magnetism in the (001) surface of gamma-Fe resulted in a lowering in the bulk-like diffusion barrier, with an ~0.2 eV barrier in the ferromagnetic surface as opposed to the ~0.6 eV in the non-magnetic surface. The high barrier for the (111) surface of gamma-Fe demonstrates that producing textured austenitic steel components with this surface exposed to the hydrogen source may work to lower the hydrogen damage in these samples. The strong effect of magnetism in lowering the barrier for diffusion demonstrates the importance of avoiding ferromagnetic austenitic steel alloys in environments where hydrogen is in abundance. These results may be applied in the process of development of Gen IV fission and fusion reactors. Ferritic and austenitic steels are ideal candidates for a number of components in these reactors, such as the first wall/breeding blanket. There is an abundance of presence of hydrogen in nuclear reactors. Hydrogen may enter the metallic matrix through diffusion processes, leading to the embrittlement of these components. Additionally, oxygen is readily present in the environment, which may oxidise components.

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Margonis, Caroline Marie. "Polyaromatic-Terminated Iron Polypyridyl Complexes For The Functionalization Of Carbon Surfaces And Electrocatalytic Hydrogen Generation." W&M ScholarWorks, 2021. https://scholarworks.wm.edu/etd/1627047877.

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Artificial Photosynthesis (AP) focuses on developing methods for the conversion of solar energy into chemical fuel in the form of H2 and O2. Heterogeneous photocatalytic systems incorporating carbon nanotubes (CNTs) have shown much promise but are currently limited and expensive due to their reliance on noble metals. To that end, this work focuses on the development and synthesis of cheaper naphthalene- and pyrene-terminated iron polypyridyl complexes for use in the simultaneous functionalization of carbon surfaces, electrocatalytic proton reduction, and eventual incorporation in photocatalytic systems. Cyclic voltammetry was used to characterize the adsorption behavior of each complex on the surface of a glassy carbon electrode. For the naphthalene variant, electrode-surface adsorption saturation was reached after 720 minutes with a maximum surface coverage of 7.7*10-11 mol/cm2, and the complex was found to be relatively surface-stable in solvents lacking hydrogen-bond donors or acceptors. Upon the addition of TFA, proton reduction catalysis occurred at -1.13 V vs. SCE in CH3CN with an overpotential of 480 mV. Additionally, the surface adsorbed naphthalene-functionalized complex was found to be active for hydrogen generation from purely aqueous buffer solutions of pH = 3.8 – 6.2. A pyrene variant was synthesized through a palladium-catalyzed amination. Its maximum surface coverage on a glassy carbon electrode was found to be 3.9*10-11mol/cm2. The complex was found to be a weak electrocatalyst for proton reduction, with proton reduction catalysis occurring at -1.00 V vs. SCE upon the addition of TFA.

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43

Sun, Yue. "The Influence of Water Chemistry on H2 Production and Uptake during Anaerobic Iron Corrosion." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/46172.

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Iron corrosion is the most important economic and aesthetic problem facing utilities. In the water distribution system, problems caused by iron corrosion include "red water", scale buildup, and pipe failures. It is necessary to improve our mechanistic understanding of anaerobic iron corrosion in order to better address these concerns. Experiments were conducted to investigate the effect of soluble constituents (Fe2+, PO43-, and NH4+) on H2 evolution during anaerobic iron corrosion. At pH 7.0 when sulfide was absent, variable Fe2+ did not have much influence on H2 release rates, whereas PO43- and NH4+ promoted H2 evolution. If present, soluble sulfide controlled H2 release rates in the solutions with Fe2+ or PO43-; however, NH4+ and S2- combined to inhibit H2 release. A simplistic empirical model was developed that fit data on corrosion rates from previous researchers studying effects of sulfate-reducing bacteria (SRB) on iron corrosion. As a whole, the experimental data and the model results support the notion that water quality controls iron corrosion rates in the presence of SRB. The practical relevance of previous research is somewhat in doubt given the atypical levels of nutrients used in relation to those actually present in water and wastewater. A second phase of research was aimed at exploring the equilibrium and kinetic aspects of iron corrosion in the presence of phosphate. The hypothesis that anaerobic iron corrosion is influenced by low pressure H2 (<1 atm) buildup was examined. At pH 2.75 and pH 7.0 in the presence of 100 mg/L P-PO43-, variations in H2 release were measured under different circumstances. Addition of PO43- formed a protective film, possibly vivianite Fe3(PO4)2, on the iron surface that eventually stopped H2 release. However, results were consistent with the idea that corrosion is an irreversible process that is relatively insensitive to low level H2 (<1 atm). Possible alternative explanations were provided to reconcile the past research data that purportedly demonstrated that removal of H2 increased corrosion rates. A reaction that caused "decay" of H2 in the presence of high phosphate was discovered that can not be readily explained. Master of Science

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Rodrigues, Girley Ferreira. "Estudo da redução de pelotas de minérios de ferro por hidrogênio e mistura de hidrogênio com monóxido de carbono." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-26122014-153022/.

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O problema da emissão de gases de efeito estufa é uma questão que tem ganhado destaque nas recentes convenções internacionais. Adiciona-se a esta questão o fato de o setor siderúrgico ser responsável por parcela significativa nas emissões de gases de efeito estufa. O presente trabalho tem por objetivos estudar processos de redução de minérios de ferro usando hidrogênio e hidrogênio mais monóxido de carbono como redutor para o processo de redução, visando assim à diminuição nas quantidades de CO2 liberadas pelo processo de redução de minérios de ferro. Os minérios foram caracterizados por Microscopia Eletrônica de Varredura, difração de raios-X, quantificação de fases pelo método Rietveld e distribuição granulométrica. Os ensaios de redução foram realizados em balança termogravimétrica e em forno tubular horizontal. A caracterização dos produtos foi realizada usando imagens obtidas por Microscopia Eletrônica de Varredura. Foi constatado que os aumentos da temperatura de redução e do fluxo de gás redutor provocam uma maior degradação física das pelotas. Verificou-se que ocorre a formação de whiskers na superfície externa das pelotas, sendo estes mais frequentes quando do fluxo combinado de H2+CO. Verificou-se que as pelotas reduzidas por hidrogênio puro resultaram em maior porosidade tanto no corpo da pelota ou mesmo no interior das partículas. Foi constatado que ocorre a redução homogênea em todas as partículas componentes da pelota. Foi constatado também que o estudo cinético através dos métodos combinados Jump-FSIA é aplicável na redução direta de pelotas de minério de ferro por H2 e H2+CO. Nas pelotas conformadas a partir de pellet feed com maior área de superfície específica (mais ativas), tanto a cinética quanto a taxa de redução indicaram que a adição de CO ao gás redutor não influi no processo de redução. A teoria de Sestak-Berggren sugere que o mecanismo controlador na reação global é a difusão podendo estar aliado a outras etapas, compondo um mecanismo misto. The problem of the emission of greenhouse gases is an issue that has gained prominence in recent international conventions. Is added to this question the fact that the steel industry is responsible for a significant portion of emissions of greenhouse gases. The present work aims to study ways of reducing iron ore using hydrogen and hydrogen plus carbon monoxide as a reducing agent to the reduction process, thus aiming to decrease the amounts of CO2 released by reduction of iron ores process. The ores were characterized by Scanning Electron Microscopy, X-ray diffraction, phase quantification by Rietveld method and particle size distribution. The reduction assays were performed in thermogravimetric balance and horizontal tubular oven. The characterization of the products was performed using images obtained by scanning electron microscopy. It was found that increases in temperature and reduction in the flow of reducing gas cause greater physical degradation of the pellets. It was found that the formation of whiskers on the outer surface of the pellets occurs most frequently found when combined flow of H2+CO. It was found that the pellets reduced with pure hydrogen resulted in much higher porosity in the body pellet or even within the particles. It was found that the homogeneous reduction occurs in all components of the particle pellet. It was also found that the kinetic study using the combined methods Jump- FSIA applies in the direct reduction of iron ore pellets by H2 and H2+CO. In shaped pellets from pellet feed with higher specific surface area (more active), both the kinetics as the rate of reduction indicated that the addition of CO to the reducing gas has no effect on the reduction process. The Sestak - Berggren theory suggests that the mechanism controlling the overall reaction is diffusion can be combined with other steps, forming a mixed mechanism.

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Thompson, Claire Ruth. "Hydrogen production via chemical looping with La0.7Sr0.3FeO3-δ and iron oxides : a kinetic and thermodynamic study". Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/3157.

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The purpose of this thesis is to investigate the kinetic and thermodynamic performance of perovskite-type material La0.7Sr0.3FeO3-δ (LSF731) and iron oxides for use as oxygen carrier materials (OCMs) in a chemical looping water splitting processes. Chemical looping water splitting is a gas-solid reaction where the OCM is cyclically reduced and oxidised in separate steps. Typical reducing gases include carbon monoxide, methane or syngas, while for hydrogen production the oxidising gas must be water. As the oxidising and reducing gases are kept separate, where is no need to separate carbon-containing contaminants from the hydrogen product. An equilibrium limited thermodynamic model for LSF731 was created. LSF731 is able to continually change its oxygen content depending on the oxygen chemical potential of a gas mixture to which it is exposed. Wave theory was used to create expressions for reaction front velocities that would occur with mixtures of different gas (carbon monoxide and carbon dioxide or water and hydrogen) at varying ratios. Results showed that reaction front velocities were higher for carbon monoxide and carbon dioxide mixtures and both mixtures achieved a maximum reaction front velocity at a δ (oxygen non-stoichiometry) of 0.25. A series of kinetic experiments were carried out in a differential microreactor and it was found that the rate of reduction with carbon monoxide was significantly lower than the rate of oxidation with water, suggesting that although thermodynamically carbon monoxide and carbon dioxide mixtures should have higher reaction front velocities, they are in fact strongly kinetically limited. Further experiments were carried out to compare the performance of LSF731 and iron oxide in a more practical way. A reverse flow integral reactor was used with a 6 cm bed of either fresh or prereduced OCM. 100 redox cycles of 5 mol% carbon monoxide in helium and 5 mol% water in helium were performed. It was found that LSF731, when operated in a reverse flow reactor, is able to overcome equilibrium limitations which would restrict any material with a discontinuity in oxygen content versus oxygen chemical potential, such as iron oxide.

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Gao, Yuan. "Synthesis and studies of a molecular hydrogen complex of iron(II)-containing bis(diphenylphosphino)methane (dppm)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0003/MQ33377.pdf.

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47

Brännberg, Fogelström Julia. "Experimental study of the temperature profile in an iron ore pellet during reduction using hydrogen gas." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266983.

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We are facing an important challenge, to reduce the greenhouse gas emissions to make sure that we limit global warming to 2 °C, preferably 1.5 °C. Drastic changes and developing new methods may be our only chance to keep global warming under 1.5 °C. The steel production in Sweden today accounts for 10% of the CO2 emission. The joint venture HYBRIT (Hydrogen Breakthrough Ironmaking Technology), between SSAB, LKAB and Vattenfall, aims to reduce the CO2 emission by developing a method that reduces iron ore pellets with hydrogen gas, leaving only water as off-gas. From simple thermodynamic calculations, it is evident that the reduction of iron ore using hydrogen gas is an endothermic reaction, requiring heat. Based on the calculated energy requirement, the temperature at the center of the pellet should not be the same as the temperature at the surface of the pellet but instead, decrease as the reduction reaction takes place. This report presents the temperature profile at the surface and in the center of a hematite pellet during hydrogen reduction at temperatures of 600 °C, 700 °C, 800 °C and 900 °C. Ideally, the results can be implemented in a model to better simulate the reduction reaction taking place inside a hematite pellet. The experiment consists of three sub-experiments, the first measures the temperature profile of the unreduced iron ore pellet in an argon gas atmosphere, secondly, the temperature profile and mass loss are measured during reduction, lastly, the temperature profile is measured for the reduced pellet in a hydrogen atmosphere. The mass loss measured during hydrogen reduction is used to calculate the degree of reduction. The results show that the reaction rate increases with increasing temperature and concentration of H2. Additionally, a higher reduction temperature gives the largest temperature decrease inside the pellet during reduction. At 900 °C, the temperature decrease is equal to 39 °C and at 600 °C, it is equal to 3 °C. The results prove that after a certain initial stage, gas diffusion and heat conduction through the product layers play important roles in controlling the reaction rate. There is even a period where a plateau of the reduction is observed, the reaction is mostly controlled by heat transfer. Idag står vi inför en viktig utmaning, att minska utsläppen av växthusgaser och se till så att vi inte överskrider 2 °C uppvärmning, helst inte 1.5 °C. För att klara detta krävs drastiska förändringar och utvecklingar av nya metoder kan vara vår enda chans att uppnå 1.5-gradersmålet. Ståltillverkningen i Sverige idag står för 10% av CO2 utsläppen och för att bidra till att minska utsläppen av CO2 har företaget HYBRIT, vilket står för Hydrogen Brakethrough Ironmaking Technology, skapats. HYBRIT är en joint venture mellan SSAB, LKAB och Vattenfall som tillsammans vill skapa stål på ett mer miljövänligt sätt. Processen går ut på att reducera järnmalmspellets med hjälp av vätgas för att producera järnsvamp och ge ifrån sig vatten som avgas. Från enkla termodynamiska beräkningar är det lätt att inse att reduktionen med hjälp av vätgas är en endoterm process, som kräver energi. Det är genom denna kunskap som en kan föreställa sig att reduktionen av järnmalmspellets med hjälp av vätgas kommer bidra till en temperaturminskning. I denna rapport har temperaturprofilen inne i och på ytan av en hematitpellet mätts under tiden som den blivit reducerad med vätgas. Idealt kan resultaten implementeras i en modell för att bättre simulera reduktionsreaktionen som äger rum i en hematitpellets. Fyra olika reduktionstemperaturer har undersökts: 600 °C, 700 °C, 800 °C och 900 °C. Experimenten består av tre del-experiment, först mäts temperaturprofilen av den oreducerad hematitpelletsen i en argonatmosfär, sedan mäts viktminskningen och temperaturprofilen av pelleten medan den reduceras i en vätgasatmosfär, slutligen mäts temperaturprofilen av den reducerade pelleten i en argonatmosfär. Viktminskningen under reduktionen används för att beräkna reduktionsgraden under reduktionsförloppet. Resultaten visade att reduktionshastigheten ökade med ökande temperatur och koncentration av H2. Ökad temperatur gav även den största temperaturminskningen inne i pelleten då den reducerats med vätgas. Vid 900 °C uppmätes en temperaturminskning på 39 °C, varav reduktion vid 600 °C gav en temperaturminskning på 3 °C. Resultaten visar att efter en viss tids reduktion, spelar gasdiffusionen och värmeledningen genom produktlagret en viktig roll och är det som begränsar reduktions-hastigheten. Fortsatt, då hematitpelleten reducerades uppstod en platå där temperaturen var konstant och reaktionen till största delen var begränsad av värmeledningen genom produktlagret.

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Sporar, Daniel. "Sputter Deposition of Iron Oxide and Tin Oxide Based Films and the Fabrication of Metal Alloy Based Electrodes for Solar Hydrogen Production." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1183481021.

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Thesis (M.S.Ch.E.)--University of Toledo, 2007. Typescript. "Submitted as partial fulfillment of the requirements for The Master of Science degree in Chemical Engineering." Bibliography: leaves 72-77.

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McKee, David. "Nuclear Transparency and Single Particle Spectral Functions from Quasielastic A(e,e'p) Reactions up to Q2=8.1 GeV2." Washington, D.C : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Energy Research ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/824828-CBQre3/native/.

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Thesis (Ph.D.); Submitted to New Mexico State Univ., Las Cruces, NM (US); 1 May 2003. Published through the Information Bridge: DOE Scientific and Technical Information. "JLAB-PHY-03-22" "DOE/ER/40150-2731" David McKee. 05/01/2003. Report is also available in paper and microfiche from NTIS.

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Serra, Marco. "Photocatalyst based on titanium or iron semiconductors for the generation of hydrogen from water upon solar irradiation." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/48542.

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The objective of present thesis is to prepare and evaluate photocatalyst for hydrogen generation from water methanol mixture using solar light. This general objective has been accomplished by applying different methodology in material preparation as well as exploring the photocatalytic activity of novel semiconductors. In this way after a general introduction to the feed showing the relevance of solar fuels and in particular hydrogen generation, the focus of chapter 3 is, on the other and, to optimize the nature of the cocatalyst based on noble metals. In this way AuPt alloy nanoparticles with different composition will be deposited on p25 and they activity correlated with the irradiation wavelength and nature of the alloy. In chapter 4 and 5 we evaluate the photocatalytic activity of materials derived from titanate nanotubes either by hydrogen annealing ad various temperature (chapter 4) or by forming heterojunction with a combination of titania nanoparticles (chapter 5). The two final chapter of this thesis report the semiconductor behaviour and the photocatalytic activity of framework phosphate either mixed valence titanium III/IV (chapter 6) or iron (chapter 7) doped with various metal. The overall results achieved show that is possible to increase the photocatalytic activity of titanium-based materials by apply concept like control of morphology, amorphization of surface of particles, formation of heterojunction and control of the cocatalyst. We have also shows behind oxide, framework phosphate can also be valuable as photocatalysts. Serra, M. (2015). Photocatalyst based on titanium or iron semiconductors for the generation of hydrogen from water upon solar irradiation [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48542 TESIS

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Dissertations / Theses on the topic 'Hydrogen on Iron'

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