Journal articles: 'Carbone Catalyse Fer'

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Hu, Sihai, Yaoguo Wu, Hairui Yao, Cong Lu, and Chengjun Zhang. "Enhanced Fenton-like removal of nitrobenzene via internal microelectrolysis in nano zerovalent iron/activated carbon composite." Water Science and Technology 73, no. 1 (September 15, 2015): 153–60. http://dx.doi.org/10.2166/wst.2015.467.

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The efficiency of Fenton-like catalysis using nano zerovalent iron (nZVI) is limited by nZVI aggregation and activity loss due to inactive ferric oxide forming on the nZVI surface, which hinders electron transfer. A novel iron–carbon composite catalyst consisting of nZVI and granular activated carbon (GAC), which can undergo internal iron–carbon microelectrolysis spontaneously, was successfully fabricated by the adsorption–reduction method. The catalyst efficiency was evaluated in nitrobenzene (NB) removal via the Fenton-like process (H2O2-nZVI/GAC). The results showed that nZVI/GAC composite was good for dispersing nZVI on the surface of GAC, which permitted much better removal efficiency (93.0%) than nZVI (31.0%) or GAC (20.0%) alone. Moreover, iron leaching decreased from 1.28 to 0.58 mg/L after reaction of 240 min and the oxidation kinetic of the Fenton-like reaction can be described well by the second-order reaction kinetic model (R2 = 0.988). The composite catalyst showed sustainable catalytic ability and GAC performed as a medium for electron transfer in internal iron–carbon microelectrolysis to promote Fe2+ regeneration and Fe3+/Fe2+ cycles. Therefore, this study represents an important method to design a low cost and high efficiency Fenton-like catalyst in practical application.

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Sun, Xinhui, Antonios Arvanitis, Devaiah Damma, Noe T. Alvarez, Vesselin Shanov, Panagiotis G. Smirniotis, and Junhang Dong. "Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions." Catalysts 10, no. 8 (August 12, 2020): 927. http://dx.doi.org/10.3390/catal10080927.

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A nanocrystalline chromium-doped ferrite (FeCr) catalyst was shown to coproduce H2 and multiwalled carbon nanotubes (MWCNTs) during water gas shift (WGS) reaction in a H2-permselective zeolite membrane reactor (MR) at reaction pressures of ~20 bar. The FeCr catalyst was further demonstrated in the synthesis of highly crystalline and dimensionally uniform MWCNTs from a dry gas mixture of CO and CH4, which were the apparent sources for MWCNT growth in the WGS MR. In both the WGS MR and dry gas reactions, the operating temperature was 500 °C, which is significantly lower than those commonly used in MWCNT production by chemical vapor deposition (CVD) method from CO, CH4, or any other precursor gases. Extensive ex situ characterizations of the reaction products revealed that the FeCr catalyst remained in partially reduced states of Fe3+/Fe2+ and Cr6+/Cr3+ in WGS membrane reaction while further reduction of Fe2+ to Fe0 occurred in the CO/CH4 dry gas environments. The formation of the metallic Fe nanoparticles or catalyst surface dramatically improved the crystallinity and dimensional uniformity of the MWCNTs from dry gas reaction as compared to that from WGS reaction in the MR. Reaction of the CO/CH4 mixture containing 500 ppmv H2S also resulted in high-quality MWCNTs similar to those from the H2S-free feed gas, demonstrating excellent sulfur tolerance of the FeCr catalyst that is practically meaningful for utilization of biogas and cheap coal-derived syngas.

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Gholami, Fatemeh, Zahra Gholami, Martin Tomas, Veronika Vavrunkova, Somayeh Mirzaei, and Mohammadtaghi Vakili. "Promotional Effect of Manganese on Selective Catalytic Reduction of NO by CO in the Presence of Excess O2 over M@La–Fe/AC (M = Mn, Ce) Catalyst." Catalysts 10, no. 11 (November 13, 2020): 1322. http://dx.doi.org/10.3390/catal10111322.

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The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.

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Yang, Ruiguang, Guiying Li, and Changwei Hu. "The preparation of Fe/wood-based activated carbon catalyst for phenol hydroxylation from Fe2+ and Fe3+ precursors." Catalysis Science & Technology 5, no. 4 (2015): 2486–95. http://dx.doi.org/10.1039/c4cy01705f.

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Johnsson, M., and M. Nygren. "Carbothermal synthesis of TaC whiskers via a vapor-liquid-solid growth mechanism." Journal of Materials Research 12, no. 9 (September 1997): 2419–27. http://dx.doi.org/10.1557/jmr.1997.0320.

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Tantalum carbide whiskers have been synthesized via a vapor-liquid-solid (VLS) growth mechanism in the temperature region 1200–1300 °C in nitrogen or argon. The starting materials consisted of Ta2O5, C, Ni, and NaCl. Carbon was added to reduce tantalum pentoxide, via a carbothermal reduction process, and Ni was used to catalyze the whisker growth. Thermodynamic calculations showed that tantalum is transported in the vapor phase as an oxochloride rather than as a chloride. An alkali metal chloride such as NaCl can be used as a source of Cl. The formation of TaC whiskers was found to be strongly dependent on the processing conditions used, on the choice of precursor materials, e.g., their particle sizes, and on the mixing procedure. So far we have obtained TaC whisker in a yield of 75–90 vol %. These whiskers are 0.1–0.6 μm in diameter and 10–30 μm in length, and they are straight and exhibit smooth surfaces. The main impurities are TaC particles, minor amounts of unreacted carbon, and remnants of the Ni catalyst.

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Hernandez-Aldave, Sandra, and Enrico Andreoli. "Fundamentals of Gas Diffusion Electrodes and Electrolysers for Carbon Dioxide Utilisation: Challenges and Opportunities." Catalysts 10, no. 6 (June 26, 2020): 713. http://dx.doi.org/10.3390/catal10060713.

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Electrocatalysis plays a prominent role in the development of carbon dioxide utilisation technologies. Many new and improved CO2 conversion catalysts have been developed in recent years, progressively achieving better performance. However, within this flourishing field, a disconnect in catalyst performance evaluation has emerged as the Achilles heel of CO2 electrolysis. Too often, catalysts are assessed in electrochemical settings that are far removed from industrially relevant operational conditions, where CO2 mass transport limitations should be minimised. To overcome this issue, gas diffusion electrodes and gas-fed electrolysers need to be developed and applied, presenting new challenges and opportunities to the CO2 electrolysis community. In this review, we introduce the reader to the fundamentals of gas diffusion electrodes and gas-fed electrolysers, highlighting their advantages and disadvantages. We discuss in detail the design of gas diffusion electrodes and their operation within gas-fed electrolysers in both flow-through and flow-by configurations. Then, we correlate the structure and composition of gas diffusion electrodes to the operational performance of electrolysers, indicating options and prospects for improvement. Overall, this study will equip the reader with the fundamental understanding required to enhance and optimise CO2 catalysis beyond the laboratory scale.

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Aswie, Viqhi, Lailatul Qadariyah, and Mahfud Mahfud. "Pyrolysis of Microalgae Chlorella sp. using Activated Carbon as Catalyst for Biofuel Production." Bulletin of Chemical Reaction Engineering & Catalysis 16, no. 1 (March 25, 2021): 205–13. http://dx.doi.org/10.9767/bcrec.16.1.10316.205-213.

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Microalgae, as a potential raw material for biofuel, has several advantages compared to other biomass. One effective way to convert microalgae into biofuel is by thermal cracking or pyrolysis, and using a catalyst or not. So far, studies on the use of microalgae, that are converted into biofuels, is still use highly concentrated catalysts in packed bed reactors, which is not economical. Therefore, the aim of this study is to convert Chlorella sp. into biofuels with conventional pyrolysis without and using an activated carbon catalyst using packed bed reactor with bubble column. The reaction temperature is 400–600 °C, pyrolysis time is 1–4 hours, and the active carbon catalyst concentration is 0–2%. The 200 grams of Chlorella sp. and the catalyst was mixed in a fixed bed reactor under vacuum (−3 mm H20) condition. Next, we set the reaction temperature. When the temperature was reached, the pyrolysis was begun. After certain time was reached, the pyrolysis produced a liquid oil product. Oil products are measured for density and viscosity. The results showed that the conventional pyrolysis succeeded in converting microalgae Chlorella sp. into liquid biofuels. The highest yield of total liquid oil is obtained 50.2 % (heavy fraction yield, 43.75% and light fraction yield, 6.44%) at the highest conditions which was obtained with 1% activated carbon at a temperature and pyrolysis time of 3 hours. Physical properties of liquid biofuel are density of 0.88 kg/m3 and viscosity of 5.79 cSt. This physical properties are within the range of the national biodiesel standard SNI 7182-2012. The packed bed reactor completed with bubble column is the best choice for converting biofuel from microalgae, because it gives different fractions, so that it is easier to process further to the commercial biofuel stage. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Motta, M. S., A. Moisala, I. A. Kinloch, and A. H. Windle. "The Role of Sulphur in the Synthesis of Carbon Nanotubes by Chemical Vapour Deposition at High Temperatures." Journal of Nanoscience and Nanotechnology 8, no. 5 (May 1, 2008): 2442–49. http://dx.doi.org/10.1166/jnn.2008.500.

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Sulphur has been recognised as a growth promoter for carbon fibres and carbon nanotubes for over 30 years. Moreover, the Fe-C-S system, in particular, has been extensively studied for more than half a century in the fields of steelmaking and cast iron. In the present work we examine the role of sulphur in the iron-catalysed growth of carbon nanotubes during the process of direct spinning of fibres from the gas phase. A detailed microstructural characterisation of the reaction products was conducted by high resolution TEM and EELS composition mapping on a dedicated FEG STEM (VG HB 501) equipped with Cs aberration correctors. Our results agree with previous works in classical metallurgy, indicating that sulphur forms a layer on the surface of the catalyst particles that plays a role in encouraging nanotube growth by surface diffusion.

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Kobayashi, Yasukazu, and Riki Hikosaka. "Analyzing Loose Contact Oxidation of Diesel Engine Soot and Ag/CeO2 Catalyst Using Nonlinear Regression Analysis." Bulletin of Chemical Reaction Engineering & Catalysis 12, no. 1 (April 30, 2017): 14. http://dx.doi.org/10.9767/bcrec.12.1.606.14-23.

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Loose contact (LC) oxidation kinetics of carbon black (CB) model soot and Ag/CeO2 catalyst was deduced from thermogravimetric analysis (TG) experiments. In the LC mode at ≧750 K, CB particles were likely to be combusted also by non-catalyzed oxidation, especially those particles located far from the catalyst surface, as well as Ag/CeO2-catalyed oxidation. Since the non-catalyzed oxidation is not due to catalytic activity, in order to deduce the catalytic activity from TG data, a nonlinear regression analysis method was proposed in this study to extract only the catalyzed oxidation part of the TG data. It was verified that this was successfully done with the equations used by the very good curve fits to the experimental TG data, and the catalytic activity was correctly obtained from LC samples with various degrees of physical contact between the CB and catalyst. Copyright © 2016 BCREC GROUP. All rights reservedReceived: 18th July 2016; Revised: 12nd September 2016; Accepted: 20th September 2016How to Cite: Kobayashi, Y., Hikosaka, R. (2017). Analyzing Loose Contact Oxidation of Diesel Engine Soot and Ag/CeO2 Catalyst Using Nonlinear Regression Analysis. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1): 14-23 (doi:10.9767/bcrec.12.1.606.14-23)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.606.14-23

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Gu, Jun, Chia-Shuo Hsu, Lichen Bai, Hao Ming Chen, and Xile Hu. "Atomically dispersed Fe3+ sites catalyze efficient CO2 electroreduction to CO." Science 364, no. 6445 (June 13, 2019): 1091–94. http://dx.doi.org/10.1126/science.aaw7515.

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Currently, the most active electrocatalysts for the conversion of CO2 to CO are gold-based nanomaterials, whereas non–precious metal catalysts have shown low to modest activity. Here, we report a catalyst of dispersed single-atom iron sites that produces CO at an overpotential as low as 80 millivolts. Partial current density reaches 94 milliamperes per square centimeter at an overpotential of 340 millivolts. Operando x-ray absorption spectroscopy revealed the active sites to be discrete Fe3+ ions, coordinated to pyrrolic nitrogen (N) atoms of the N-doped carbon support, that maintain their +3 oxidation state during electrocatalysis, probably through electronic coupling to the conductive carbon support. Electrochemical data suggest that the Fe3+ sites derive their superior activity from faster CO2 adsorption and weaker CO absorption than that of conventional Fe2+ sites.

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Li, Da Wei, Lu Jun Pan, Juan Juan Qian, and He Ma. "High Efficient Synthesis of Carbon Nanocoils by Catalysts Produced by a Fe and Sn Containing Solution." Advanced Materials Research 60-61 (January 2009): 251–55. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.251.

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Chemical vapor deposition, Catalyst, Carbon nanocoils, High efficient growth Abstract: Carbon nanocoils (CNCs) were prepared by thermal chemical vapor deposition (CVD) using a Fe and Sn containing solution as the catalyst predecessor. The solutions of Fe2(SO4)3/SnCl2, FeCl3/SnCl2 and Fe(NO3)3/SnCl2 with the mol ratios of 3:0.1 to 3:1 were used as catalysts. Comparing the catalysts in different composition ratios with the grown deposits after CVD, we found that the optimum mol ratio between Fe and Sn is 6:0.1. It is noted that the catalyst combination of Fe2(SO4)3 /SnCl2 obviously increases the quantity of the grown carbon deposits indicating that it has the largest catalytic activity among the three kinds of combinations. Large surface area of catalyst films formed by release of SO3 from the decomposition of Fe2(SO4)3 over the temperature of 480 °C is very good for the carbon nanocoils growth and the introduction of sulfide impurities are the key factors leading to the high efficient growth for carbon nanocoils. It is known that Fe-additions lead to the growth of carbon nanotubes or nanofibers, while Sn induces their helical growth and a little sulfur impurities may induce the efficient growth of carbon nanocoils.

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Huang, Yao-Hui, Hau-Cheng Wei, and Hung-Ta Chen. "Heterogeneous photo-catalysis system for the degradation of azo dye Reactive Black 5 (RB5)." Water Science and Technology 65, no. 2 (January 1, 2012): 221–26. http://dx.doi.org/10.2166/wst.2012.202.

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This study investigated a heterogeneous photo-catalysis system by introducing a novel brick supported iron oxide (denoted as B1) for the heterogeneous photoassisted degradation of Reactive Black 5 (RB5) at pH value from 3 to 7 in a three-phase (gas–liquid–solid) fluidized bed reactor (3P-FBR). Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD) and N2 adsorption/desorption were used to characterize the B1 catalyst. The in situ formation of hydrogen peroxide and the depletion of oxalic acid by photochemical cycle of Fe(III)-oxalate complex under UVA light (λ = 365 nm) were studied. The effects of the solution pH and the concentration of oxalic acid on the degradation of RB5 are elucidated. About 90% decolourization was measured and 80% of the total organic carbon (TOC) was eliminated at pH 5.0 after 120 min for 20 mg/L RB5 in presence of 10 g/L B1 catalyst, 30 mg/L oxalic acid under 15 W UVA light. A mechanism for the photocatalytic degradation of RB5 over B1 catalyst is proposed.

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Azara, Abir, El-Hadi Benyoussef, Faroudja Mohellebi, Mostafa Chamoumi, François Gitzhofer, and Nicolas Abatzoglou. "Catalytic Dry Reforming and Cracking of Ethylene for Carbon Nanofilaments and Hydrogen Production Using a Catalyst Derived from a Mining Residue." Catalysts 9, no. 12 (December 14, 2019): 1069. http://dx.doi.org/10.3390/catal9121069.

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In this study, iron-rich mining residue (UGSO) was used as a support to prepare a new Ni-based catalyst via a solid-state reaction protocol. Ni-UGSO with different Ni weight percentages wt.% (5, 10, and 13) were tested for C2H4 dry reforming (DR) and catalytic cracking (CC) after activation with H2. The reactions were conducted in a differential fixed-bed reactor at 550–750 °C and standard atmospheric pressure, using 0.5 g of catalyst. Pure gases were fed at a molar ratio of C2H4/CO2 = 3 for the DR reaction and C2H4/Ar = 3 for the CC reaction. The flow rate is defined by a GHSV = 4800 mLSTP/h.gcat. The catalyst performance is evaluated by calculating the C2H4 conversion as well as carbon and H2 yields. All fresh, activated, and spent catalysts, as well as deposited carbon, were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), temperature programmed reduction (TPR), and thermogravimetric analysis (TGA). The results so far show that the highest carbon and H2 yields are obtained with Ni-UGSO 13% at 750 °C for the CC reaction and at 650 °C for the DR reaction. The deposited carbon was found to be filamentous and of various sizes (i.e., diameters and lengths). The analyses of the results show that iron is responsible for the growth of carbon nanofilaments (CNF) and nickel is responsible for the split of C–C bonds. In terms of conversion and yield efficiencies, the performance of the catalytic formulations tested is proven at least equivalent to other Ni-based catalyst performances described by the literature.

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Miletto, Ivana, Enrico Catizzone, Giuseppe Bonura, Chiara Ivaldi, Massimo Migliori, Enrica Gianotti, Leonardo Marchese, Francesco Frusteri, and Girolamo Giordano. "In Situ FT-IR Characterization of CuZnZr/Ferrierite Hybrid Catalysts for One-Pot CO2-to-DME Conversion." Materials 11, no. 11 (November 14, 2018): 2275. http://dx.doi.org/10.3390/ma11112275.

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CO2 hydrogenation to dimethyl ether (DME) is a promising strategy to drive the current chemical industry towards a low-carbon scenario since DME can be used as an eco-friendly fuel as well as a platform molecule for chemical production. A Cu‒ZnO‒ZrO2/ferrierite (CZZ/FER) hybrid grain was recently proposed as a catalyst for CO2-to-DME one-pot conversion exhibiting high DME productivity thanks to the unique shape-selectivity offered by ferrierite zeolite. Nevertheless, such a catalyst deactivates but no direct evidence has been reported of activity loss over time. In this work, CZZ/FER catalysts with different acidity levels were characterized with the FTIR technique before and after reactions, aiming to give new insights about catalyst deactivation. Results show that activity loss can be related to both (i) copper particle sintering, which decreases CO2 activation towards methanol, and (ii) acidity loss due to H+/Cu2+ ion exchange.

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Wu, Yuzhe, Yuntong Li, Jie Mao, Haiyang Wu, Tong Wu, Yaying Li, Birong Zeng, Yiting Xu, Conghui Yuan, and Lizong Dai. "Metallosupramolecular Polymer Precursor Design for Multi-Element Co-Doped Carbon Shells with Improved Oxygen Reduction Reaction Catalytic Activity." Catalysts 9, no. 1 (January 18, 2019): 102. http://dx.doi.org/10.3390/catal9010102.

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Heteroatom-doped carbon materials have been extensively studied in the field of electrochemical catalysis to solve the challenges of energy shortage. In particular, there is vigorous research activity in the design of multi-element co-doped carbon materials for the improvement of electrochemical performance. Herein, we developed a supramolecular approach to construct metallosupramolecular polymer hollow spheres, which could be used as precursors for the generation of carbon shells co-doped with B, N, F and Fe elements. The metallosupramolecular polymer hollow spheres were fabricated through a simple route based on the Kirkendall effect. The in situ reaction between the boronate polymer spheres and Fe3+ could easily control the component and shell thickness of the precursors. The as-prepared multi-element co-doped carbon shells showed excellent catalytic activity in an oxygen reduction reaction, with onset potential (Eonset) 0.91 V and half-wave (Ehalf-wave) 0.82 V vs reversible hydrogen electrode (RHE). The fluorine element in the carbon matrix was important for the improvement of oxygen reduction reaction (ORR) activity performance through designing the control experiment. This supramolecular approach may afford a new route to explore good activity and a low-cost catalyst for ORR.

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Li, Xin, Jiankang Wang, Xiao Zhang, Xianjin Hou, Hongbo Xu, Zhongping Yao, and Zhaohua Jiang. "A High-Efficient Carbon-Coated Iron-Based Fenton-Like Catalyst with Enhanced Cycle Stability and Regenerative Performance." Catalysts 10, no. 12 (December 19, 2020): 1486. http://dx.doi.org/10.3390/catal10121486.

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Carbon coated iron-based Fenton-like catalysts are now widely studied in wastewater treatment. However, their poor stability is still a big challenge and the related regenerative performance is seldom investigated. Herein, a carbon-coated Fe3O4 on carbon cloth (cc/Fe3O4@C) was prepared with glucose as carbon source via electrodeposition and ethanol solvothermal methods. An amorphous carbon layer with polar C-groups covers the surface of Fe3O4, which presents a flaky cross-linked network structure on the carbon cloth (cc). The cc/Fe3O4@C exhibits an improved catalytic activity with nearly 84% phenol was removed within 35 min with polar C-groups. What’s more, around 80% phenol can still be degraded in 120 min after 14 degradation cycles. After the regeneration treatment, the degradation performance was restored to the level of the fresh in the first two regenerations. The enhanced cycle stability and regeneration performance of the catalyst are as follows: Firstly, the catalyst’s composition and structure were recovered; Secondly, the reduction effect of the amorphous carbon layer ensuring timely supplement of Fe2+ from Fe3+. Also, the carbon layer reduces Fe leaching during the Fenton-like process.

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Hussain, Zahid, Romana Wiedner, Kerstin Steiner, Tanja Hajek, Manuela Avi, Bianca Hecher, Angela Sessitsch, and Helmut Schwab. "Characterization of Two Bacterial Hydroxynitrile Lyases with High Similarity to Cupin Superfamily Proteins." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 2053–55. http://dx.doi.org/10.1128/aem.06899-11.

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ABSTRACTHydroxynitrile lyases (HNLs) catalyze the cleavage of cyanohydrins. In the reverse reaction, they catalyze the formation of carbon-carbon bonds by enantioselective condensation of hydrocyanic acid with carbonyls. In this study, we describe two proteins from endophytic bacteria that display activity in the cleavage and the synthesis reaction of (R)-mandelonitrile with up to 74% conversion of benzaldehyde (enantiopreferenceee89%). Both showed high similarity to proteins of the cupin superfamily which so far were not known to exhibit HNL activity.

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Chou, Loiland, and Lobo. "Reverse Water-Gas Shift Iron Catalyst Derived from Magnetite." Catalysts 9, no. 9 (September 14, 2019): 773. http://dx.doi.org/10.3390/catal9090773.

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The catalytic properties of unsupported iron oxides, specifically magnetite (Fe3O4), were investigated for the reverse water-gas shift (RWGS) reaction at temperatures between 723 K and 773 K and atmospheric pressure. This catalyst exhibited a fast catalytic CO formation rate (35.1 mmol h−1 gcat.−1), high turnover frequency (0.180 s−1), high CO selectivity (> 99%), and high stability (753 K, 45000 cm3h−1gcat.−1) under a 1:1 H2 to CO2 ratio. Reaction rates over the Fe3O4 catalyst displayed a strong dependence on H2 partial pressure (reaction order of ~0.8) and a weaker dependence on CO2 partial pressure (reaction order of 0.33) under an equimolar flow of both reactants. X-ray powder diffraction patterns and XPS spectra reveal that the bulk composition and structure of the post-reaction catalyst was formed mostly of metallic Fe and Fe3C, while the surface contained Fe2+, Fe3+, metallic Fe and Fe3C. Catalyst tests on pure Fe3C (iron carbide) suggest that Fe3C is not an effective catalyst for this reaction at the conditions investigated. Gas-switching experiments (CO2 or H2) indicated that a redox mechanism is the predominant reaction pathway.

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Kumar, Arun. "Natural Materials—Interesting Candidates for Carbon Nanomaterials." Physchem 1, no. 1 (January 19, 2021): 4–25. http://dx.doi.org/10.3390/physchem1010002.

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This review sums up the techniques used for the synthesis of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon nanospheres (CNSs) by employing catalysts of natural origin. Establishing large-scale production and commercial applications of CNTs for a sustainable society is still of high apprehension. In this regard, one of the major factors is the starting materials such as precursors and catalyst sources. However, natural materials contain a minor quantity of metals or metal oxides and could be employed as a catalyst source for the synthesis of CNTs, providing the possibility to replace expensive catalyst sources. A large number of successful studies have been completed so far and confirm that these developed methods for carbon nanomaterials synthesis exhibiting high quality from common natural materials are not only possible but, most importantly, promising and scalable. This review also highlights purification methods and recent promising applications of as-synthesized CNTs.

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Xiao, Tiancun, Tara Shirvani, Oliver Inderwildi, Sergio Gonzalez-Cortes, Hamid AlMegren, David King, and Peter P. Edwards. "The Catalyst Selectivity Index (CSI): A Framework and Metric to Assess the Impact of Catalyst Efficiency Enhancements upon Energy and CO2 Footprints." Topics in Catalysis 58, no. 10-11 (July 2, 2015): 682–95. http://dx.doi.org/10.1007/s11244-015-0401-1.

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AbstractHeterogeneous catalysts are not only a venerable part of our chemical and industrial heritage, but they also occupy a pivotal, central role in the advancement of modern chemistry, chemical processes and chemical technologies. The broad field of catalysis has also emerged as a critical, enabling science and technology in the modern development of “Green Chemistry”, with the avowed aim of achieving green and sustainable processes. Thus a widely utilized metric, the environmental E factor—characterizing the waste-to-product ratio for a chemical industrial process—permits one to assess the potential deleterious environmental impact of an entire chemical process in terms of excessive solvent usage. As the many (and entirely reasonable) societal pressures grow, requiring chemists and chemical engineers not only to develop manufacturing processes using new sources of energy, but also to decrease the energy/carbon footprint of existing chemical processes, these issues become ever more pressing. On that road to a green and more sustainable future for chemistry and energy, we note that, as far as we are aware, little effort has been directed towards a direct evaluation of the quantitative impacts that advances or improvements in a catalyst’s performance or efficiency would have on the overall energy or carbon (CO2) footprint balance and corresponding greenhouse gas (GHG) emissions of chemical processes and manufacturing technologies. Therefore, this present research was motivated by the premise that the sustainability impact of advances in catalysis science and technology, especially heterogeneous catalysis—the core of large-scale manufacturing processes—must move from a qualitative to a more quantitative form of assessment. This, then, is the exciting challenge of developing a new paradigm for catalysis science which embodies—in a truly quantitative form—its impact on sustainability in chemical, industrial processes. Towards that goal, we present here the concept, definition, design and development of what we term the Catalyst Sensitivity Index (CSI) to provide a measurable index as to how efficiency or performance enhancements of a heterogeneous catalyst will directly impact upon the fossil energy consumption and GHG emissions balance across several prototypical fuel production and conversion technologies, e.g. hydrocarbon fuels synthesized using algae-to-biodiesel, algae-to-jet biofuel, coal-to-liquid and gas-to-liquid processes, together with fuel upgrading processes using fluidized catalytic cracking of heavy oil, hydrocracking of heavy oil and also the production of hydrogen from steam methane reforming. Traditionally, the performance of a catalyst is defined by a combination of its activity or efficiency (its turnover frequency), its selectivity and stability (its turnover number), all of which are direct manifestations of the intrinsic physicochemical properties of the heterogeneous catalyst itself under specific working conditions. We will, of course, retain these definitions of the catalytic process, but now attempt to place discussions about a catalyst’s performance onto a new foundation by investigating the effect of improvements in the catalyst’s efficiency or performance on the resulting total energy and total CO2 footprint for these prototypical fuel production and fuel conversion processes. The CSI should help the academic and industrial chemical communities, not only to highlight the current ‘best practice catalysts’, but also draw specific conclusions as to what energy and CO2 emissions saving one could anticipate with higher efficiency/higher performance from heterogeneous catalysts in a particular fuel synthesis or conversion process or technology. Our aim is to place discussions about advances in the science and technology of catalysis onto a firm foundation in the context of GHG emissions. We believe that thinking about (and attempting to quantify) total energy and CO2 emissions reductions associated with advances in catalysis science from a complete energy life cycle analysis perspective is extremely important. The CSI will help identify processes where the most critical advances in catalyst efficiency are needed in terms of their potential impact in the transition to a more sustainable future for fuel production and conversion technologies.

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Hodaifa, Gassan, Cristina Agabo García, and Rafael Borja. "Study of Catalysts’ Influence on Photocatalysis/Photodegradation of Olive Oil Mill Wastewater. Determination of the Optimum Working Conditions." Catalysts 10, no. 5 (May 17, 2020): 554. http://dx.doi.org/10.3390/catal10050554.

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The high production of raw olive oil mill wastewater (OMW) is a current environmental problem due to its high organic load and phenol compounds. In this work, photo-Fenton reaction as an advanced oxidation process has been chosen for OMW treatment. In this sense, different iron salts (FeCl3, Fe2(SO4)3, FeSO4·7H2O, and Fe(ClO4)3) as catalysts were used in order to compare their effects on treatment. For each catalyst, different H2O2 concentrations (2.5, 5.0, 7.5, 10.0, 15.0, 20.0, and 30.0%, w/v) as oxidizing agents were tested. The common experimental conditions were temperature 20 °C, the catalyst/H2O2 ratio = 0.03, pH = 3, and ultraviolet light. The Lagergren kinetic model, in cases of total organic carbon removal, for the best H2O2 concentration per catalyst was used. During the experiments, the water quality was determined by measuring the removal percentages on chemical oxygen demand, total carbon, total organic carbon, total nitrogen, total phenolic compounds, total iron, turbidity and electric conductivity. The best catalyst was FeCl3 and the optimum H2O2 concentration was 7.5% (w/v). At these optimal conditions, the removal percentages for chemical oxygen demand, total phenolic compounds, total carbon, total organic carbon and total nitrogen were 60.3%, 88.4%, 70.1%, 63.2% and 51.5%, respectively.

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Wang, Luhui, Rong Hu, Hui Liu, Qinhong Wei, Dandan Gong, Liuye Mo, Hengcong Tao, and Zhonghuai Zhang. "Encapsulated Ni@La2O3/SiO2 Catalyst with a One-Pot Method for the Dry Reforming of Methane." Catalysts 10, no. 1 (December 28, 2019): 38. http://dx.doi.org/10.3390/catal10010038.

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Ni nanoparticles encapsulated within La2O3 porous system (Ni@La2O3), the latter supported on SiO2 (Ni@La2O3)/SiO2), effectively inhibit carbon deposition for the dry reforming of methane. In this study, Ni@La2O3/SiO2 catalyst was prepared using a one-pot colloidal solution combustion method. Catalyst characterization demonstrates that the amorphous La2O3 layer was coated on SiO2, and small Ni nanoparticles were encapsulated within the layer of amorphous La2O3. During 50 h of dry reforming of methane at 700 °C and using a weight hourly space velocity (WHSV) of 120,000 mL gcat−1 h−1, the CH4 conversion obtained was maintained at 80%, which is near the equilibrium value, while that of impregnated Ni–La2O3/SiO2 catalyst decreased from 63% to 49%. The Ni@La2O3/SiO2 catalyst exhibited very good resistance to carbon deposition, and only 1.6 wt% carbon was formed on the Ni@La2O3/SiO2 catalyst after 50 h of reaction, far lower than that of 11.5 wt% deposited on the Ni–La2O3/SiO2 catalyst. This was mainly attributed to the encapsulated Ni nanoparticles in the amorphous La2O3 layer. In addition, after reaction at 700 °C for 80 h with a high WHSV of 600,000 mL gcat−1 h−1, the Ni@La2O3/SiO2 catalyst exhibited high CH4 conversion rate, ca. 10.10 mmol gNi−1 s−1. These findings outline a simple synthesis method to prepare supported encapsulated Ni within a metal oxide porous structure catalyst for the dry reforming of methane reaction.

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Cavell, KJ. "Metal Chelate Systems as Catalysts for Olefin and Carbon Monoxide Conversion Reactions." Australian Journal of Chemistry 47, no. 5 (1994): 769. http://dx.doi.org/10.1071/ch9940769.

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The application of non-phosphine-based chelating ligands in homogeneous catalyst systems is a surprisingly recent and relatively unexplored area of research. Chelating ligands can concurrently stabilize intermediates, control catalyst activity and direct the product distribution far more effectively than monodentate ligands. In this review our studies with catalyst systems containing chelate ligands primarily of the β-diketonate type [dithio-β-diketonate (sacsac); monothio-β-diketonate (sacac); and imino β-diketonate (nacac) ligands] is discussed. Examples of the catalyst systems show enzyme-like superactivity. Studies modelling these catalyst systems have provided valuable information relating the effects of ligand modifications to reaction pathways and to activities. Our most recent investigations of simple chelating ligands based on picolinic acid are also discussed. Studies modelling CO/ethene insertion/elimination with extremely labile alkylplatinum picolinate complexes led to the development of new single-component nickel oligomerization catalysts.

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Le, Thanh Son. "STUDY OF SOME PARAMETERS RESPONSIBLE FOR GLYPHOSATE HERBICIDE MINERALIZATION BY ELECTRO - FENTON PROCESS." Vietnam Journal of Science and Technology 55, no. 4C (March 24, 2018): 238. http://dx.doi.org/10.15625/2525-2518/55/4c/12158.

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Glyphosate (C3H8NO3P) is a highly effective broad-spectrum, post-emergence, non- selective organophosphate herbicide and commonly applied in Viet Nam. The removal of glyphosate in aqueous solution has been investigated by electro - fenton process which is based on the continuous production of ●OH radicals by reaction between Fe2+ catalyst and H2O2 electrochemical generated on cathode. The carbon felt (60 cm2) and Pt gauze (45 cm2) were used as cathode and anode of the electro-fenton system, successively. Monitoring the total organic carbon (TOC) during the electrolysis proved that pH, current intensity, electrolysis time and catalyst concentration influenced the glyphosate mineralization efficiency. At the optimal conditions: [Fe2+] = 0.1 mM; pH = 3; [Na2SO4] = 0.05M ; I = 0.5A and the compressed air was bubbled through the solutions, the experiment results showed that 84.4 % Glyphosate was mineralized to CO2, H2O and inorganic acid after 50 min.

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Eom, Seungwook, Seyoung Ahn, and Sanghwan Jeong. "Electrochemical Activity of a La0.9Ca0.1Co1−xFexO3Catalyst for a Zinc Air Battery Electrode." Journal of Nanomaterials 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/724064.

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The optimum composition of cathode catalyst has been studied for rechargeable zinc air battery application. La0.9Ca0.1Co1−xFexO3 (x=0–0.4)perovskite powders were prepared using the citrate method. The substitution ratio of Co2+with Fe3+cations was controlled in the range of 0–0.4. The optimum substitution ratio of Fe3+cations was determined by electrochemical measurement of the air cathode composed of the catalyst, polytetrafluoroethylene (PTFE) binder, and Vulcan XC-72 carbon. The substitution by Fe enhanced the electrochemical performances of the catalysts. Considering oxygen reduction/evolution reactions and cyclability, we achieved optimum substitution level ofx=0.1in La0.9Ca0.1Co1−xFexO3.

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Singh Rana, Prem Jyoti, Pallavi Singh, and Prasenjit Kar. "Carbon nanoparticles for ferric ion detection and novel HFCNs–Fe3+composite for NH3and F−estimation based on a “TURN ON” mechanism." Journal of Materials Chemistry B 4, no. 35 (2016): 5929–37. http://dx.doi.org/10.1039/c6tb00975a.

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Hollow fluorescent carbon nanoparticle and solid fluorescent carbon nanoparticle were synthesised separately fromSyzygium cuminiextractviaa self-catalysis method in large scale for commercialization without providing any external heat. The nanoparticles were charaterized and their applications studied.

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Zhang, Zhen, Junya Zhang, Xiaokun Ye, Yongyou Hu, and Yuancai Chen. "Pd/RGO modified carbon felt cathode for electro-Fenton removing of EDTA-Ni." Water Science and Technology 74, no. 3 (May 27, 2016): 639–46. http://dx.doi.org/10.2166/wst.2016.215.

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Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as nickel due to its strong chelation. The electro-Fenton (EF) process using a cathode made from palladium (Pd), reduced graphene oxide (RGO) and carbon felt, fed with air, exhibited high activities and stability for the removal of 10 mg L−1 EDTA-Ni solution. Pd/RGO catalyst was prepared by one-pot synthesis; the scanning electron microscopy and X-ray diffraction analysis indicated nanoparticles and RGO were well distributed on carbon felt, forming three dimensional architecture with both large macropores and a mesoporous structure. The cyclic voltammetric results showed that the presence of RGO in Pd/RGO/carbon felt significantly increased the current response of two-electron reduction of O2 (0.45 V). The key factors influencing the removal efficiency of EDTA-Ni, such as pH, current and Fe2+ concentration, were investigated. Under the optimum conditions, the removal efficiency of EDTA-Ni reached 83.8% after 100 min EF treatment. Mechanism analysis indicated that the introduction of RGO in Pd/RGO/carbon felt significantly enhanced the electrocatalytic activities by inducing •OH in the EF process; direct H2O2 oxidation still accounted for a large amount of EDTA-Ni removal efficiency.

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Yuan, Rongfang, Beihai Zhou, and Li Ma. "Removal of toluene from water by photocatalytic oxidation with activated carbon supported Fe3+-doped TiO2 nanotubes." Water Science and Technology 70, no. 4 (June 14, 2014): 642–48. http://dx.doi.org/10.2166/wst.2014.239.

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In this work, activated carbon (AC)-supported TiO2 containing 1.0% (mass percent) of 1.0 at.% (atomic percent) Fe3+-doped TiO2 nanotubes (Fe-TNTs) were successfully synthesized. The catalyst was used to effectively decompose toluene in water under O3/UV conditions, and some properties including the morphology, X-ray photoelectron spectroscopy, X-ray diffraction patterns, specific surface area and UV-visible diffuse reflectance spectroscopy were analyzed. A removal efficiency of 90.7% was achieved in the presence of fresh AC-supported Fe-TNTs calcined at 550 °C, with a pseudo-first-order rate constant of 0.038/min. The removal efficiency of toluene was reduced when the catalysts were repeatedly used, since the amount of adsorption sites of the supporting substrates decreased. However, even after AC-supported catalyst was used four times, the removal efficiency of toluene was still sufficient in water treatment. The enhanced photocatalytic activity of AC-supported Fe-TNTs was related to the synergistic effect of AC adsorption and Fe-TNTs photocatalytic ozonation. The water from a petrochemical company in China was used to obtain the removal efficiency of the pollutants, and the toluene and total organic carbon removal efficiencies were 69.9% and 58.3%, respectively.

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Cheng, Yujie, Qingdi Sun, Liyun Huang, Qian He, Hao Zhang, Pengbo Wang, Ying Zhang, et al. "Protein powder derived nitrogen-doped carbon supported atomically dispersed iron sites for selective oxidation of ethylbenzene." Dalton Transactions 50, no. 34 (2021): 11711–15. http://dx.doi.org/10.1039/d1dt02001c.

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Alvisi, Marco, Giovanna Galtieri, L. Giorgi, Emanuele Serra, Tiziana Di Luccio, and R. Giorgi. "Evolution of Pt Nanoclusters Morphology on PEMFC Electrode due to Methanol Oxidation Reaction Studied by Electron Microscopy and Synchrotron Grazing Incidence X-Ray Diffraction." Advances in Science and Technology 51 (October 2006): 181–86. http://dx.doi.org/10.4028/www.scientific.net/ast.51.181.

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The proton exchange membrane fuel cells (PEMFC) have been developed mainly as a power source for vehicles, power generation and consumer electronics since they combine high energy conversion efficiency at relatively low temperatures without pollutants emission in the environment. An electrode for a PEMFC is a layered structure composed by a catalyst layer deposited on a porous carbon substrate. The substrate is usually covered by a diffusion layer that enhances the gas and water flow. Platinum nanoparticles supported by carbon microparticles are commonly employed as catalyst layer. In this work an extreme ultra-low loading of Pt catalyst (< 0.02 mg/cm2) has been deposited by magnetron sputtering on gas diffusion electrodes, with different carbon supports (Vulcan and SuperP), in order to enhance the activity of PEM fuel cells. The morphology (shape and grain size) and microstructure have been studied combining field emission scanning electron microscopy (FEG-SEM), grazing incidence synchrotron x-ray diffraction (GIXRD) and x-ray photoelectron spectroscopy (XPS). The results presented here concern the evolution of the cluster size and shape after the ageing, induced by cyclic voltammetry for methanol oxidation reaction.

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Moon, Sook Young, In Ji Kang, Seung Min Kim, and Woo Sik Kim. "Influence of the Sulfur Content Catalyst on the Packing Density of Carbon Nanotube Forests." Nanomaterials 9, no. 6 (June 17, 2019): 889. http://dx.doi.org/10.3390/nano9060889.

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For the fabrication of high-performance carbon nanotube (CNT) composites with practical applicability, the development of new methods for the controlled growth of high-aspect-ratio CNTs still constitutes a challenge. With the aim of gaining a deeper understanding of the catalytic CNT growth, in this study, the effect of the catalyst composition is investigated using different mixtures of Fe2(SO4)3 and FeCl2 as catalysts. The relationship between the catalyst chemical state and the growth behavior of CNT forests is demonstrated by evaluating the alignment, diameter, length, and areal density of the CNT forests. When the Fe2(SO4)3 content is increased, the area density, the IG/ID ratio, and the crystallite size of the CNTs increase. Additionally, the obtained CNT forests exhibit good spinnability with increasing the sulfur content.

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32

Gvoic, Vesna, Miljana Prica, Djurdja Kerkez, Milena Becelic-Tomin, Aleksandra Kulic, Anita Leovac-Macerak, and Bozo Dalmacija. "Oxidative degradation of cyan flexo dye with Heterogeneous Fenton reagent - Fe2(MoO4)3 particle." Acta Periodica Technologica, no. 50 (2019): 77–85. http://dx.doi.org/10.2298/apt1950077g.

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Heterogeneous Fenton catalyst Fe2(MoO4)3 was prepared and the process efficiency was evaluated for oxidation of water-based Cyan flexo dye in synthetic aqueous solution and printing wastewater. The removal process of printing dye was analyzed by UV/VIS spectrophotometry, while dye mineralization was evaluated by the determination of total organic carbon content and chemical oxygen demand. Four determinants of the heterogeneous Fenton system, including initial dye concentration, iron concentration, pH and hydrogen peroxide concentration were investigated. Statistical method, definitive screening design was applied to generate optimal operational conditions of the four variables, which maximizes the process of dye removal. The initial dye concentration of 20 mgL-1, catalyst dosage of 0.75 mgL-1, pH of 2 and H2O2 concentration of 11 mM were chosen as the best operational conditions, contributing to 82% of the process efficiency. The Fenton process efficiency of 79% was achieved within the treatment of printing wastewater under optimal conditions for a 90 minute reaction time. The maximum COD removal efficiency was 61.1%, while 67% mineralization was achieved. The obtained results confirmed synergistic effect of Fe3+ and MoO4 2? which contributed to high catalytic activity and high heterogeneous Fenton efficiency.

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Putri, Reza Audina, Safni Safni, Diana Vanda Wellia, Upita Septiani, and Novesar Jamarun. "Degradasi Zat Warna Orange-F3R dan Violet-3B secara Sonolisis Frekuensi Rendah dengan Penambahan Katalis C-N-Codoped TiO2." Jurnal Kimia Valensi 5, no. 1 (May 29, 2019): 35–43. http://dx.doi.org/10.15408/jkv.v5i1.7801.

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Zat warna orange-F3R dan violet-3B merupakan zat warna organik sintetis turunan vat yang bersifat non-biodegradable. Degradasi kedua zat warna ini telah dilakukan secara sonolisis dengan penambahan katalis semikonduktor TiO2 anatase yang didoping karbon dan nitrogen. Proses sonolisis menggunakan iradiasi ultrasonik dengan frekuensi 35 kHz. Massa katalis optimum yang diperoleh untuk sonolisis zat warna orange-F3R adalah 9 mg dan 6 mg untuk violet-3B. Persen degradasi meningkat secara signifikan dengan penambahan katalis yaitu dari 8.3% menjadi 36.2% untuk sonolisis zat warna orange-F3R selama iradiasi 180 menit. Sedangkan, dengan waktu iradiasi yang sama persen degradasi dari zat warna violet meningkat dari 5.8% menjadi 34.2% setelah penambahan katalis. Kata kunci: C-N-codoped TiO2, sonolisis, ultrasonik, vat Orange-F3R and violet-3B are non-biodegradable synthetic organic dyes. The degradation of these two dyestuffs has been done by sonolysis process with the addition of semiconductor TiO2 anatase catalyst which is doped by carbon and nitrogen atoms. The sonolysis process used ultrasonic irradiation with a frequency of 35 kHz. The optimum catalyst mass obtained for the orange-F3R dye sonolysis was 9 mg and 6 mg for violet-3B. The percentage of degradation increased significantly with the addition of the catalyst; it was from 8.3% to 36.2% for the orange-F3R dye during irradiation for 180 min. Meanwhile, by the same irradiation time, the degradation percentage of violet dye increased from 5.8% to 34.2% after the addition of the catalyst. Keywords: C-N-codoped TiO2, sonolysis, ultrasonic, vat-dye.

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34

Hu, Dengping, Guangyao Zhang, Juan Wang, and Qin Zhong. "Carbon-Supported Spinel Nanoparticle MnCo2O4 as a Cathode Catalyst towards Oxygen Reduction Reaction in Dual-Chamber Microbial Fuel Cell." Australian Journal of Chemistry 68, no. 6 (2015): 987. http://dx.doi.org/10.1071/ch14516.

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The poor kinetics of oxygen reduction reaction (ORR) in neutral media and ambient temperature limit the performance of microbial fuel cells (MFCs). So higher-performing, low-cost oxygen reduction catalysts play a key role in power output. Through direct nanoparticle nucleation and growth on carbon black, a nanocomposite of manganese cobaltite and carbon black (in situ-MnCo2O4/C) was synthesized via a facile hydrothermal method. Subsequently, the in situ-MnCo2O4/C samples were characterized. The results show that the MnCo2O4 nanoparticles with a crystalline spinel structure are well dispersed on carbon black. Electrochemical measurements reveal that in situ-MnCo2O4/C demonstrates excellent ORR catalytic activity, which may account for the synergetic coupling effect between MnCo2O4 and carbon black. The ORR on as-prepared in situ-MnCo2O4/C hybrid mainly favours a direct 4-electron reaction pathway in alkaline solution. Moreover, in situ-MnCo2O4/C was used as an alternative catalyst for ORR in dual-chamber MFC. The obtained maximum power density is 545 mW m–2, which is far higher than that of the plain cathode (Pmax = 214 mW m–2) and slightly lower than that of commercial Pt/C catalyst (Pmax = 689 mW m–2). This study implies that in situ-MnCo2O4/C nanocomposite is an efficient and cost-effective cathode catalyst for practical MFC application.

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Brown, David P., Albert G. Nasibulin, and Esko I. Kauppinen. "CFD-Aerosol Modeling of the Effects of Wall Composition and Inlet Conditions on Carbon Nanotube Catalyst Particle Activity." Journal of Nanoscience and Nanotechnology 8, no. 8 (August 1, 2008): 3803–19. http://dx.doi.org/10.1166/jnn.2008.453.

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The evolution of iron catalyst particles during aerosol (floating catalyst) Chemical Vapor Deposition (CVD) synthesis of Carbon Nanotubes (CNTs) from CO is computed using a multi species Computational Fluid Dynamics (CFD) model incorporating a lognormal aerosol method of moments (MOM) to describe their dynamics and a combined chemical kinetics and equilibrium model for catalytic production of CO2. The influence of the presence of iron at the reactor walls, the fed particle size, number concentration and polydispersity and the effect of the catalytic production of CO2 at the reactor wall are studied in terms of particle size, concentration and polydispersity and reagent concentration during CNT synthesis. It is found that iron catalyst particle dynamics are essentially insensitive to wall iron concentrations and, for a wide range of particle sizes and concentrations, it is found that the catalyst particles are stable up to a critical CNT window in which CNT nucleation and growth occurs. Concentrations of catalyst particles significantly above 1 × 1014 #/m3, however, lead to poor control over catalyst particle size and polydispersity at the CNT nucleation front which, in turn, leads to poor control over CNT diameter. The location of the growth window is shown to be directly associated with the availability of catalytically produced CO2 diffusing from the reactor walls to the reactor core. These results help to explain the large variations in CNT diameter and chirality and the inefficient use of catalyst material in other floating catalyst CNT processes based on in-situ catalyst particle synthesis.

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Arhoutane, Mohamed Reda, Ghizlan Kaichouh, Muna Shueai Yahya, Miloud El Karbane, Hind Chakchak, and Kacem El Kacemi. "Elimination of gatifloxacin from water: Treatment by electro-Fenton process and highlighting of a biological post-treatment." Mediterranean Journal of Chemistry 8, no. 4 (June 6, 2019): 308–19. http://dx.doi.org/10.13171/mjc841906066mra.

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This study concerns the oxidative degradation and mineralization of gatifloxacin in aqueous solution at pH = 3 and in the presence of Fe2+ as catalyst Â using electro-Fenton (EF) process, with carbon felt as a cathode and platinum as an anode. The mineralization is evaluated by the chemical oxygen demand by assessing the applied current value and concentration of catalyst Fe2+. Some stable by-products of gatifloxacin have been identified using high-performance liquid chromatography and liquid chromatography tandem mass spectrometry. The second part of this paper concerns the study of the biodegradability in determining of BOD5/COD during the mineralization of gatifloxacin by EF in order to evaluate the possibility of coupling electro-Fenton process with the biological one. This leads to an efficient treatment of water contaminated by this antibiotic with lower cost.

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Buasri, A., B. Ksapabutr, M. Panapoy, and N. Chaiyut. "Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC)." International Journal of Renewable Energy Development 1, no. 3 (November 3, 2012): 81. http://dx.doi.org/10.14710/ijred.1.3.81-86.

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: The continuous production of ethyl ester was studied by using a steady-state fixed bed reactor (FBR). Transesterification of palm stearin (PS) and waste cooking palm oil (WCPO) with ethanol in the presence of calcium oxide impregnated palm shell activated carbon (CaO/PSAC) solid catalyst was investigated. This work was determined the optimum conditions for the production of ethyl ester from PS and WCPO in order to obtain fatty acid ethyl ester (FAEE) with the highest yield. The effects of reaction variables such as residence time, ethanol/oil molar ratio, reaction temperature, catalyst bed height and reusability of catalyst in a reactor system on the yield of biodiesel were considered. The optimum conditions were the residence time 2-3 h, ethanol/oil molar ratio 16-20, reaction temperature at 800C, and catalyst bed height 300 mm which yielded 89.46% and 83.32% of the PS and WCPO conversion, respectively. CaO/PSAC could be used repeatedly for 4 times without any activation treatment and no obvious activity loss was observed. It has potential for industrial application in the transesterification of triglyceride (TG). The fuel properties of biodiesel were determined. Keywords: biodiesel, calcium oxide, ethyl ester, fixed bed reactor, palm shell activated carbon

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Hu, Xiao Dong, Hua Deng, and Lin Du. "Preparation and Characterization of Fe³⁺ / TiO₂ Thin Films Loaded Activated Carbon and Degradation of Methyl Orange." Advanced Materials Research 332-334 (September 2011): 134–37. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.134.

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Sol - gel method and doped with Fe3+ modification techniques were used, prepared for high catalytic activity of iron-doped titanium dioxide nanoparticles,which loaded on the activated carbon for Degradation of Methyl Orange. Such as crystal structure, particle size, load morphology, chemical state and optical absorption characteristics of the doped titania nanoparticles were characterized by using XRD, SEM, and UV-Vis. Fe-TiO2 catalysts for visible light response and the catalytic degradation of methyl orange in water performance were studied. The results showed that: catalysts prepared were anatase, the particle size decreases with the more amount of iron-doped. The phenomenon of Fe3+-modified TiO2 red shift were obviously. Compared with the undoped catalyst,degradation of Fe3+-TiO2 containing activated carbon improved significantly both in the UV and fluorescent light.

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Markova, E. B., A. G. Cherednichenko, L. S. Akhmedova, Yu M. Averina, and Yu M. Serov. "Research into Thermocatalytic Propane-to-Propylene Synthesis Using Iron-Containing Composite Carbon Materials." Herald of the Bauman Moscow State Technical University. Series Natural Sciences, no. 4 (97) (August 2021): 100–114. http://dx.doi.org/10.18698/1812-3368-2021-4-100-114.

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The development of modern thermocatalytic technologies for processing oil and gas raw materials is one of the promising areas for the advancement of chemical production. New highly efficient catalytic systems with the required technical characteristics and long service life play an essential role in solving these issues. The paper focuses on obtaining propylene by selective propane dehydrogenation. In the course of the experiments, composite iron-containing catalysts were synthesized, in which the active component is iron oxide in combination with an inert carbon matrix. FAS activated carbon and carbon nanotubes were used as the matrix. As a result of the synthesis on the catalyst surface it was possible to obtain catalytic centers that transfer electrons by changing the degree of iron oxidation when converting the starting materials into the target reaction products. Findings of research show that the obtained iron-containing catalysts significantly increase the efficiency of the process in comparison with the efficiency of thermal cracking of propane. Thus, the Fe3+/FAS catalyst showed a conversion rate of the initial reagent of 68 % and a propylene selectivity of about 42 %. Further transition to catalytic systems based on singlelayer and double-layer carbon nanotubes modified with iron oxide (Fe3+/CNTI and Fe3+/CNTII) made it possible to obtain propane conversion up to 37--40 % with a decrease in propylene selectivity to 29--30 %. Studies of the service life of the synthesized catalytic systems and the possibility of their regeneration show that, with account for the regeneration, the activity of the catalysts and the main technical characteristics of the propane-to-propylene cracking process remain unchanged for 10 working cycles

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Zhao, Pingping, Hanqiu Nie, Jiahao Yu, Jianbo Wang, and Gongzhen Cheng. "A facile synthesis of porous N-doped carbon with hybridization of Fe3C nanoparticle-encased CNTs for an advanced oxygen reduction reaction electrocatalyst." Inorganic Chemistry Frontiers 5, no. 10 (2018): 2546–53. http://dx.doi.org/10.1039/c8qi00681d.

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Excellent ORR catalysis activity in both alkaline and acid media was found in porous N-doped carbon hybridized with Fe₃C nanoparticle-encased CNTs by annealing ZIF-8, FeC₂O₄ and cyanoguanidine.

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Karaeva, Aida, Sergey Urvanov, Nikita Kazennov, Eduard Mitberg, and Vladimir Mordkovich. "Synthesis, Structure and Electrical Resistivity of Carbon Nanotubes Synthesized over Group VIII Metallocenes." Nanomaterials 10, no. 11 (November 17, 2020): 2279. http://dx.doi.org/10.3390/nano10112279.

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The paper reports the synthesis of carbon nanotubes from ethanol over group VIII (Fe, Co, Ni) catalysts derived from corresponding metallocenes. Several unexpected cooperative effects are reported, which are never observed in the case of individual metallocenes such as the commonly used ferrocene catalyst Fe(C5H5)2. The formation of very long (up to several µm) straight monocrystal metal kernels inside the carbon nanotubes was the most interesting effect. The use of trimetal catalysts (Fe1-x-yCoxNiy)(C5H5)2 resulted in the sharp increase in the yield of carbon nanotubes. The electrical conductivity of the produced nanotubes is determined by the nature of the catalyst. The variation of individual metals in the Ni-Co-Fe leads to a drop of the electrical resistivity of nanotube samples by the order of magnitude, i.e., from 1.0 × 10−3 to 1.1 × 10−5 Ω∙m. A controlled change in the electrophysical properties of the nanotubes can make it possible to expand their use as fillers in composites, photothermal and tunable magnetic nanomaterials with pre-designed electrical conductivity and other electromagnetic properties.

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Oyama, Keishi, Kyohei Takamatsu, Kaito Hayashi, Yuji Aoki, Shigeto Kuroiwa, Tsuyoshi Hirajima, and Naoko Okibe. "Carbon-Assisted Bioleaching of Chalcopyrite and Three Chalcopyrite/Enargite-Bearing Complex Concentrates." Minerals 11, no. 4 (April 19, 2021): 432. http://dx.doi.org/10.3390/min11040432.

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Overcoming the slow-leaching kinetics of refractory primary copper sulfides is crucial to secure future copper sources. Here, the effect of carbon was investigated as a catalyst for a bioleaching reaction. First, the mechanism of carbon-assisted bioleaching was elucidated using the model chalcopyrite mineral, under specified low-redox potentials, by considering the concept of Enormal. The carbon catalyst effectively controlled the Eh level in bioleaching liquors, which would otherwise exceed its optimal range (0 ≤ Enormal ≤ 1) due to active regeneration of Fe3+ by microbes. Additionally, Enormal of ~0.3 was shown to maximize the carbon-assisted bioleaching of the model chalcopyrite mineral. Secondly, carbon-assisted bioleaching was tested for three types of chalcopyrite/enargite-bearing complex concentrates. A trend was found that the optimal Eh level for a maximum Cu solubilization increases in response to the decreasing chalcopyrite/enargite ratio in the concentrate: When chalcopyrite dominates over enargite, the optimal Eh was found to satisfy 0 ≤ Enormal ≤ 1. As enargite becomes more abundant than chalcopyrite, the optimal Eh for the greatest Cu dissolution was shifted to higher values. Overall, modifying the Eh level by adjusting AC doses to maximize Cu solubilization from the concentrate of complex mineralogy was shown to be useful.

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Khattab, Mohammed A., Heba A. El-Deeb, and Azza El-Maghraby. "Influence of the Catalyst Supporting Material on the Growth of Carbon Nanotubes." Advanced Materials Research 1163 (April 2021): 117–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1163.117.

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Catalytic chemical vapor deposition (CCVD) is considered as the most suitable technique for the large scale and low-cost production of carbon nanotubes (CNTs). Catalytic activity of Fe-Co, Fe-Ni and Co-Ni mixture supported on Al2O3 has been investigated in the production of carbon nanotubes (CNTs). Absolute ethanol was used as a source of carbon and nitrogen as the carrier gas. The Carbon nanotubes prepared by the catalytic decomposition of ethanol at 1173°K over iron supported alumina or silica catalysts with 5Wt% iron loading in a horizontal tube furnace under flow of nitrogen. The morphological structure of deposits CNTs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the alumina supported catalysts more active towards CNTs formation than silica supported catalysts even with changing the percentage of metal loading (2.5% - 10%). Further investigation for alumina support with other metals and their binary metals heve been done to see for how far the alumina is suitable as a support. The yield of the carbon deposit obtained varied from 11.2 to 34.9% of the initial weight of the catalyst. The results revealed that CNTs prepared by Fe-Ni/Al2O3 catalyst has high length/diameter ratio and small tube diameter ≈ 17 nm.

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Wen, Yicun, Rui Zhang, Yu Cang, Jianchao Zhang, Lixiao Liu, Xuhong Guo, and Bin Fan. "Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2." Polish Journal of Chemical Technology 17, no. 1 (March 1, 2015): 62–65. http://dx.doi.org/10.1515/pjct-2015-0010.

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Abstract The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper. As far as we know, it is the first time to use potassium bicarbonate only as the catalyst in the production process which is simple and cheap. Satisfactory conversion rate of propylene oxide and yield of the products could be achieved at the optimized conditions with quite a small amount of by-products. Our new method offers an attractive choice for the production of dimethyl carbonate in large-scale industry efficiently and environmental friendly.

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Yanase, Takashi, Takuya Miura, Tatsuya Shiratori, Mengting Weng, Taro Nagahama, and Toshihiro Shimada. "Synthesis of Carbon Nanotubes by Plasma-Enhanced Chemical Vapor Deposition Using Fe1−xMnxO Nanoparticles as Catalysts: How Does the Catalytic Activity of Graphitization Affect the Yields and Morphology?" C 5, no. 3 (August 8, 2019): 46. http://dx.doi.org/10.3390/c5030046.

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The choice of a catalyst for carbon nanotube (CNT) growth is critical to controlling the morphology and chirality of the final product. Plasma-enhanced chemical vapor deposition (PECVD) can alleviate the requirements of the catalyst, i.e., they must be active for both the decomposition of the source gas and graphitization in the conventional thermal CVD. However, it is still not well understood how the catalytic activity of the graphitization affects the yield and quality of CNTs. In this paper, we systematically investigated the influence of the catalytic activity of graphitization by tuning the composition of Fe1−xMnxO (x = 0–1) nanoparticles as catalysts. As the Mn component increased, the number of CNTs decreased because Mn has no catalytic function of the graphitization. The quality of CNTs also affected by the inclusion of the Mn component. Our study may provide useful information to develop a new catalyst for CNT growth in PECVD.

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Kol'tsov, Nikolay I., and Vladislav Kh Fedotov. "STUDY OF CARBON DIOXIDE ADSORPTION ON CHROMOXIDE CATALYST ON NON-STATIONARY CONCENTRATIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 7 (June 18, 2018): 37. http://dx.doi.org/10.6060/ivkkt.20186107.5714.

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Investigation of the regularities of chemical processes, not only near but also far from the stationary state, gives additional information on their mechanisms. In this paper, we present a new method for estimating rate constants of adsorption-desorption processes from the experimentally measured values of the nonstationary concentrations of an adsorbed substance, based on calculating the instantaneous rates of the adsorption (or desorption) process. This method allows to connect unknown kinetic parameters of adsorption (desorption) of a substance on the catalyst surface for various most probable assumed mechanisms with the calculated values of the instantaneous rates of adsorption-desorption processes. As a consequence, the method makes it possible to solve two types of inverse problems of chemical kinetics: calculate point and interval values of rates constants of adsorption and desorption; determine the most likely mechanism from several proposed mechanisms of implementation of these processes. Using this method, point and interval values of the rates constants of adsorption and desorption of carbon dioxide were determined on the base of nonstationary experimental data on adsorption on the assumption of carbon dioxide adsorption on a chromoxide catalyst to three proposed mechanisms: linear, bimolecular and dissociative. Based on the results of calculations, the corresponding non-stationary dependences of carbon dioxide adsorption were restored, which were compared with the experimental data. The obtained results confirm that the previously established dissociative mechanism of adsorption of carbon dioxide on the chromoside catalyst is the most probable. The developed simple method does not require the use of complex optimization calculations and can be used to solve the inverse problem of chemical kinetics associated with the determination of mechanisms and the estimation of the rates constants of adsorption and desorption of substances on various catalysts.Forcitation:Kol’tsov N.I., Fedotov V.Kh. Study of carbon dioxide adsorption on chromoxide catalyst on non-stationary concentrations. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 37-42

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Wang, Xueyang, Yuanjun Liu, Tiange Wei, Xuefeng Song, Xiaofang Cheng, Xiaoping Shen, and Guoxing Zhu. "Fe3+–Co2+ species loaded on carbon as an effective pre-catalyst for oxygen evolution." New Journal of Chemistry 44, no. 48 (2020): 21326–31. http://dx.doi.org/10.1039/d0nj04934d.

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Yamada, Koji, Kentaro Abe, Masafumi Mikami, Morihiro Saito, and Jun Kuwano. "Synthesis of Carbon Nanotubes from Polycyclic Compounds by CVD Method." Key Engineering Materials 320 (September 2006): 163–66. http://dx.doi.org/10.4028/www.scientific.net/kem.320.163.

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Multi-walled carbon nanotubes (MWCNTs) were synthesized from camphor by a chemical vapor deposition (CVD) method in a range of 750-900. The catalyst was fed in three ways: (a) a sputtered Fe-film on a quartz substrate (b) vaporized ferrocene in an Ar flow; (c) both of (a) and (b). In the case (c), highly pure, dense and aligned MWCNT arrays formed on the quartz substrate at 850, whereas nonaligned MWCNTs formed in the cases (a) and (b).

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Yang, Ji, Jiawang Liu, Helfried Neumann, Robert Franke, Ralf Jackstell, and Matthias Beller. "Direct synthesis of adipic acid esters via palladium-catalyzed carbonylation of 1,3-dienes." Science 366, no. 6472 (December 19, 2019): 1514–17. http://dx.doi.org/10.1126/science.aaz1293.

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The direct carbonylation of 1,3-butadiene offers the potential for a more cost-efficient and environmentally benign route to industrially important adipic acid derivatives. However, owing to the complex reaction network of regioisomeric carbonylation and isomerization pathways, a selective practical catalyst for this process has thus far proven elusive. Here, we report the design of a pyridyl-substituted bidentate phosphine ligand (HeMaRaphos) that, upon coordination to palladium, catalyzes adipate diester formation from 1,3-butadiene, carbon monoxide, and butanol with 97% selectivity and 100% atom-economy under industrially viable and scalable conditions (turnover number > 60,000). This catalyst system also affords access to a variety of other di- and triesters from 1,2- and 1,3-dienes.

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Al-Mubaddel, Fahad, Samsudeen Kasim, Ahmed A. Ibrahim, Abdulrhman S. Al-Awadi, Anis H. Fakeeha, and Ahmed S. Al-Fatesh. "H2 Production from Catalytic Methane Decomposition Using Fe/x-ZrO2 and Fe-Ni/(x-ZrO2) (x = 0, La2O3, WO3) Catalysts." Catalysts 10, no. 7 (July 16, 2020): 793. http://dx.doi.org/10.3390/catal10070793.

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An environmentally-benign way of producing hydrogen is methane decomposition. This study focused on methane decomposition using Fe and Fe-Ni catalysts, which were dispersed over different supports by the wet-impregnation method. We observed the effect of modifying ZrO2 with La2O3 and WO3 in terms of H2 yield and carbon deposits. The modification led to a higher H2 yield in all cases and WO3-modified support gave the highest yield of about 90% and was stable throughout the reaction period. The reaction conditions were at 1 atm, 800 °C, and 4000 mL(hgcat)−1 space velocity. Adding Ni to Fe/x-ZrO2 gave a higher H2 yield and stability for ZrO2 and La2O3 + ZrO2-supported catalysts whose prior performances and stabilities were very poor. Catalyst samples were analyzed by characterization techniques like X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), thermo-gravimetric analysis (TGA), and Raman spectroscopy. The phases of iron and the supports were identified using XRD while the BET revealed a significant decrease in the specific surface areas of fresh catalysts relative to supports. A progressive change in Fe’s oxidation state from Fe3+ to Fe0 was observed from the H2-TPR results. The carbon deposits on Fe/ZrO2 and Fe/La2O3 + ZrO2 are mainly amorphous, while Fe/WO3 + ZrO2 and Fe-Ni/x-ZrO2 are characterized by graphitic carbon.

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Journal articles on the topic 'Carbone Catalyse Fer'

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