Relevant bibliographies by topics / Al2O3 catalysts

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Academic literature on the topic 'Al2O3 catalysts'

Author: Grafiati
Published: 4 June 2021
Last updated: 15 February 2022

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Journal articles on the topic "Al2O3 catalysts"

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Thassanaprichayanont, Sildara, Duangduen Atong, and Viboon Sricharoenchaikul. "Preparation of Ni – MgO– La2O3 Catalyst on Alumina Support for Catalytic Tar Cracking Process." Key Engineering Materials 434-435 (March 2010): 826–29. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.826.

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This study reported the synthesis of Ni -based catalysts on Al2O3 support carried out by two different methods including co-impregnation and sequential impregnation. Different nitrate solutions of nickel, lanthanum, and magnesium were used for support impregnation. The calination process was carried out at 650 °C and 850 °C for 2 h under air. The XRD patterns of the catalyst samples presented main phases of Al2O3 and other diffraction lines corresponding to metal and oxide promoters; Ni, MgO and/or NiO, (Ni,Mg)Al2O4, La2O3 and La(AlO3). Prepared catalysts appeared in irregular shaped agglomerates of small particles of less than 1 micron. Surface area of co-impregnated catalysts increased with increasing calcination temperature while ones from sequential impregnation decreased except for those last impregnated with nickel salts. The La2O3-MgO-Ni/Al2O3 sequential impregnated catalyst had the highest surface area of 8.0-8.5 m2/g.
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Mardwita, Mardwita, Eka Sri Yusmartini, and Nidya Wisudawati. "Effects of Calcination Temperatures on The Catalytic Activities of Alumina Supported Cobalt and Chromium Catalysts." Bulletin of Chemical Reaction Engineering & Catalysis 14, no. 3 (December 1, 2019): 654. http://dx.doi.org/10.9767/bcrec.14.3.4673.654-659.

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Catalysts properties are important for catalytic reactions. The interaction between support and metal in a catalyst is resulted from catalyst preparation. In this study, gamma-alumina (Al2O3) supported cobalt (Co) and chromium (Cr) catalysts were prepared by impregnation method and calcined at two different temperatures, they are 400 °C for 4 hours and 800 °C for 4 hours. The resulted catalysts contained 10 wt.% of metal and denoted as Co/Al2O3(400), Co/Al2O33(800), Cr/Al2O3(400), and Cr/Al2O3(800) catalysts. The surface and state of the catalysts were examined by using x-ray diffraction (XRD), x-ray photoelectron spectrometer (XPS) and transmission electron microscopy (TEM). The XRD result reveals that strong interaction between Co and Al2O3 due to a formation of higher cobalt oxide. The XRD result further indicates aggregation and strong support metal interaction between Co and Al2O3 during calcination. On the other hand, TEM result showed that large Co particle was observed on Al2O3. The Cr/Al2O3 catalysts were characterized by using XPS. The XPS results showed that Cr/Al2O3(800) catalyst was dominated by Cr6+ species at binding energy 579.04 eV, indicating high dispersion of Cr on Al2O3. Moreover, Cr metal particle was not observed on XRD and TEM image. All the characterization results provide information that the impregnated metal on Al2O3 showed different properties. Co metal particle tends to be more oxidized and formed large particle, however it was not observed on Cr metal particle. Copyright © 2019 BCREC Group. All rights reserved
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Haerudin, Hery, Wihatmoko Waskitoaji, and Usman Usman. "EFFECT OF THE REDUCTION TEMPERATURE INTO CATALYTIC ACTIVITY OF Ni SUPPORTED BY TiO2, AL2O2 AND TiO2/AL2O3 FOR CONVERSION CO2 INTO METHANE." Indonesian Journal of Chemistry 3, no. 1 (June 7, 2010): 24–31. http://dx.doi.org/10.22146/ijc.21902.

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Nickel catalysts, containing 6% (w/w) of nickel, have been prepared using TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9). The catalysts were used for CO2 conversion into methane. The characteristics of catalysts were studied by determination of its specific surface area, temperature programmed reaction technique and X-ray diffraction. The specific surface area were varied slightly by different temperature of reduction, namely after reduction at 300°C it was 39, 120 and 113 m2/g and after reduction at 400°C it was 42, 135 and 120 m2/g for 6% nickel catalysts supported on TiO2, Al2O3 and mixture of TiO2-Al2O3 (1:9) respectively. Temperature program reaction studies (TPO and TPR) showed that NiTiOx species were possibly formed during the pretreatments which has shown by the shift of its peak to the lower temperature on Ni catalyst, that supported on mixture of TiO2-Al2O3 compared with catalysts supported on individual TiO2 or Al2O3. The nickel species on reduced Ni catalysts supported on TiO2 and on mixture of TiO2-Al2O3 could be detected by X-ray diffraction. The catalyst's activities toward CH4 formation were affected by the reduction temperature. Activity for CH4 formation was decreased in the following order: Ni/ TiO2 > Ni/ TiO2: Al2O3 > Ni/ Al2O3 and Ni/ TiO2: Al2O3 > Ni/ TiO2> Ni/ Al2O3, when catalysts were reduced at 300°C or 400°C respectively. The CO2 conversion was decreased in the following order: Ni/ Al2O3 > Ni/ TiO2: Al2O3 > Ni/ TiO2 when catalysts were reduced at 300°C or 400°C respectively. Keywords: nickel catalyst, carbondioxide, methane
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Fertal, Domenica R., Maxim P. Bukhovko, Yong Ding, Mehmet Z. Billor, and Anil C. Banerjee. "Particle Size and PdO–Support Interactions in PdO/CeO2-γ Al2O3 Catalysts and Effect on Methane Combustion." Catalysts 10, no. 9 (August 30, 2020): 976. http://dx.doi.org/10.3390/catal10090976.

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In this study, we investigated the effects of sequential impregnation in two PdO/CeO2/Al2O3 nanocatalysts (4Pd-20CeO2/Al2O3 and 20CeO2-4Pd/Al2O₃) on catalytic properties, particle sizes, and metal oxide–support interactions. Pulse chemisorption indicated significantly higher dispersion and smaller particle size in the 20CeO2-4Pd/Al2O₃ catalyst. STEM images of the 4Pd-20CeO2/Al2O₃ catalyst showed PdO nanoparticles on the surface of crystalline Al2O₃. In the 20CeO2-4Pd/Al2O3 catalyst, PdO nanoparticles were strongly embedded on ceria indicating PdO-ceria interactions. Both supports were on separate sites in the two catalysts suggesting weak interactions. PdO particle sizes were 6–12 nm in the 4Pd-20CeO2/Al2O₃ catalyst and 4–8 nm in the 20CeO2-4Pd/Al2O₃ catalyst. Methane conversion was 100% at 275 °C after a 20-min run with the 4Pd-20CeO2/Al2O3 catalyst compared to 25% conversion by the 20CeO2-4Pd/Al2O₃ catalyst under same conditions. The support alumina could stabilize the PdO species and facilitated oxygen migration on the surface and from the bulk in the 4Pd-20CeO2/Al2O3 catalyst. The lower activities in the 20CeO2-4Pd/Al2O₃ catalyst could be due to inaccessibility of PdO active sites at low temperature due to embedment of PdO nanoparticles on ceria. We could infer from our data that sequence of impregnation in catalyst synthesis could significantly influence catalytic properties and methane combustion due to PdO–support interactions.
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Yang, Haobo, Jichao Li, Hao Yu, Feng Peng, and Hongjuan Wang. "Metal-Foam-Supported Pd/Al2O3 Catalysts for Catalytic Combustion of Methane: Effect of Interaction between Support and Catalyst." International Journal of Chemical Reactor Engineering 13, no. 1 (March 1, 2015): 83–93. http://dx.doi.org/10.1515/ijcre-2014-0009.

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Abstract Structured Pd/Al2O3 catalysts were fabricated by impregnating Pd onto Ni and Cu foams coated with Al2O3 layers. By testing the adhesion stability and catalytic activity in the combustion of methane, the superior performance of Ni-foam-supported Pd/Al2O3 catalyst was demonstrated, to its counterpart powder catalysts. The resultant structured catalysts enable the fabrication of lamellar microreactor systems. It is found that the metal foams influence the activity of catalyst layer, due to the diffusive penetration of metallic atoms into catalysts from metal foams. The Ni foam is beneficial for enhancing the activity of Pd/Al2O3 catalyst, while the Cu foam plays a negative role. The investigation to the model powder catalysts doped with Ni and Cu verified the modification of Ni and Cu to the physicochemical properties of Pd/Al2O3 catalyst, thereby the catalytic performances. Thus, it can be expected that the performance of structured catalysts may be improved by rationally designing and selecting proper supports.
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Pudi, Satyanarayana Murty, Tarak Mondal, Prakash Biswas, Shalini Biswas, and Shishir Sinha. "Conversion of Glycerol into Value-Added Products Over Cu–Ni Catalyst Supported on γ-Al2O3 and Activated Carbon." International Journal of Chemical Reactor Engineering 12, no. 1 (January 1, 2014): 151–62. http://dx.doi.org/10.1515/ijcre-2013-0102.

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Abstract A series of Cu, Ni monometallic and bimetallic catalysts supported on γ-Al2O3 and activated carbon were synthesized by incipient wetness impregnation method and examined for hydrogenolysis and esterification of glycerol. Hydrogenolysis reaction was carried out in a 250 ml Teflon-coated stainless steel batch reactor at 250°C and 10 bar H2 pressure, whereas esterification of glycerol with acetic acid was carried out at 120°C at atmospheric pressure. The physiochemical properties of the catalysts were investigated by various techniques such as surface area, X-ray diffraction (XRD), NH3-temperature-programmed desorption (TPD). Characterization results dictated that the reduction behavior, acidic nature and the metal support interactions were varied with the support as well as Cu/Ni weight ratio. The XRD results confirmed the formation of mixed oxide Cu0.75Ni0.25 Al2O4 phase in Cu–Ni (3:1)/γ-Al2O3 catalyst. Among the catalysts tested, Cu–Ni bimetallic catalysts showed superior performance as compared to monometallic catalysts in both the reactions. The glycerol hydrogenolysis activity of γ-Al2O3 supported Cu–Ni catalysts was higher than the activated carbon-supported catalysts. 1,2-PDO was obtained as the main hydrogenolysis product independent of the support as well as Cu/Ni weight ratio and its selectivity was in the range of 92.8–98.5%. The acidic nature of γ-Al2O3 and the mixed oxide (Cu0.75Ni0.25Al2O4) phase played an important role for hydrogenolysis activity. Cu–Ni (3:1)/γ-Al2O3 catalyst showed the maximum 1,2-PDO selectivity to 97% with 27% glycerol conversion after a reaction time of 5 h. On the other hand, Cu–Ni(1:3)/C catalyst showed the highest glycerol conversion of 97.4% for esterification and obtained selectivity to monoacetin, diacetin and triacetin were 26.1%, 67.2% and 6.5%, respectively.
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Yang, Shao Xia, Yu Jie Feng, Jiafeng Wan, Wanpeng Zhu, and Zhanpeng Jiang. "Effect of TiO2 on the Property of RuO2/γ-Al2O3 Catalyst." Materials Science Forum 475-479 (January 2005): 1141–44. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1141.

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A catalyst, as a kind of function material, plays important roles. In the paper RuO2/g-Al2O3 and RuO2-TiO2/g-Al2O3 catalyst were prepared by the impregnation method. The structure o f two catalysts was studied with XRD, SEM and XPS. The addition of TiO2 promoted the dispersion of Ru particles, and made the amount of the chemisorbed oxygen increased on catalyst surface. The activity was investigated in WAO of phenol over RuO2/g-Al2O3 and RuO2-TiO2/g-Al2O3 catalysts. The results showed that two catalysts had good activity, and TiO2 effectively increased the activity of RuO2/g-Al2O3 catalyst in WAO of phenol. With RuO2-TiO2/g-Al2O3 catalyst 96% phenol removal was observed at 150°C and 3MPa after 80min reaction in WAO of phenol.
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Do Pham Noa, Uy, Huan Nguyen Manh, Loc Hoang Van, Chien Luc Minh, Giang Nguyen Thi Chau, Nhan Truong Van, Binh Phan Minh Quoc, Luong Nguyen Huu, and Thuan Huynh Minh. "Fischer-Tropsch synthesis over Co/γ-Al2O3 catalyst loaded on ceramic monolith-structured substrate." Vietnam Journal of Catalysis and Adsorption 9, no. 3 (October 2, 2020): 88–93. http://dx.doi.org/10.51316/jca.2020.055.

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Cobalt-based catalyst supported on γ-Al2O3­ was prepared by impregnation method and loaded on ceramic monolith-structured substrate by wash-coating slurry method. Physico-chemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area and H2 temperatured-programmed reduction (H2-TPR). Activity of the catalysts for Fischer-Tropsch synthesis was investigated in a tubular reactor in a temperature range of 200-275 oC at 20 bar and GHSV = 3000 h-1. Co/γ-Al2O3 catalyst loaded on ceramic monolith-structured substrate enhanced efficacy of Fischer-Tropsch synthesis by increasing and stabilizing CO conversion and C5+ selectivity, compared to Co/γ-Al2O3 powder catalyst.
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Tuktin B.T.,, Shapovalova L.B.,, Tenizbayeva A.A.,, Abilmagzhanov A.Z.,, and Egizbaeva R.I.,. "HYDROTREATING AND HYDROISOMERIZATION OF OIL FRACTIONS ON MODIFIED ALUMINUM-COBALTMOLYBDENUM CATALYSTS." SERIES CHEMISTRY AND TECHNOLOGY 5, no. 443 (October 2020): 99–107. http://dx.doi.org/10.32014/2020.2518-1491.86.

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In this work we are given results and research of hydro refining of gasoline and diesel oil fractions on alumina catalysts CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3, CoO-MoO3-Ce2О3-Р2О5-ZSM-HY-Al2O3, CoO-MoO3-La2О3-Р2О5- AAC-ZSM -Al2O3. The catalysts were prepared by impregnating a mixture of aluminum hydroxide and zeolites ZSM-5, HY with aqueous solutions of salts Co, Mo, La and phosphoric acid. Large-scale laboratory tests of the synthesized catalysts were carried out in the process of hydro processing of various types of gasoline and diesel fractions. At hydro treating of straight-run gasoline over CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3 shows that in the temperature range 320 - 350оС the maximum amount of isoalkanes is formed 33.4-40.4%. The octane number of refined gasoline increases in comparison with the initial one from 78.9 to 89.3 (RON) and from 60.9 to 73.4 (MON). The sulfur content of catalysate with increasing temperature up to 400оС decreased to 0.0012 %. At hydro processing of catalytic cracking gasoline on CoO-MoO3-La2О3-Р2О5-ZSM-Al2O3 the octane number of refined gasoline is slightly reduced. The sulfur content of catalysate with increasing temperature up to 400оС decreased from initial with from 0.0134 to 0 0014 %. It was found that the lowest pour point and cloud point of hydro-refined diesel fuel is observed on the catalyst CoO-MoO3-La2O3-P2O5-ZSM-Al2O3. After hydro treating on this catalyst the pour point and cloud point are equal to minus 52.7oC and minus 40.8oC accordingly. This same catalyst has the highest hydro desulfurization activity: the sulfur content decreases from 0.5600% to 0.104%. Thus, the developed modified zeolite-containing catalysts CoO-MoO3-La2О3-P2O5-ZSM-Al2O3, CoO-MoO3-Се2О3-P2O5-ZSM-HY-Al2O3, CoO-MoO3-La2О3-P2O5-AAC-ZSM-Al2O3, exhibiting high activity at hydro treating of gasoline and diesel fractions and is able in one stage deep hydro treating, hydro isomerization and hydrocracking which allows to obtain low-sulfur, high-octane gasoline and low-sulfur and low solidifying diesel fuel which is important for operation of vehicles in winter conditions.
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Lee, Jong Kwon, Hyun Seo, Ung Gi Hong, Gle Park, Yeonshick Yoo, Jinsuk Lee, Hosik Chang, and In Kyu Song. "Platinum-Tin Nano-Catalysts Supported on Alumina for Direct Dehydrogenation of n-Butane." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 8305–10. http://dx.doi.org/10.1166/jnn.2015.11241.

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Al2O3 supports were prepared by a precipitation method using various basic solutions (NaOH, KOH, NH4OH, and Na2CO3) as precipitation agents, and Pt/Sn/Al2O3 nano-catalysts were then prepared by a sequential impregnation method. The prepared catalysts were applied to the direct dehydrogenation of n-butane to n-butenes and 1,3-butadiene. The effect of precipitation agents on the physicochemical properties and catalytic activities of Pt/Sn/Al2O3 nano-catalysts in the direct dehydrogenation of n-butane was investigated. Catalytic performance of Pt/Sn/Al2O3 nanocatalysts decreased in order of Pt/Sn/Al2O3 (NaOH) > Pt/Sn/Al2O3 (KOH) > Pt/Sn/Al2O3 (NH4OH) > Pt/Sn/Al2O3 (Na2CO3). Among the catalysts tested, Pt/Sn/Al2O3 (NaOH) nano-catalyst showed the best catalytic performance in terms of yield for total dehydrogenation products (TDP, n-butenes and 1,3-butadiene). Hydrogen chemisorption experiments revealed that platinum surface area of the catalyst was closely related to the catalytic performance. Yield for TDP increased with increasing platinum surface area of the catalyst.
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Dissertations / Theses on the topic "Al2O3 catalysts"

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KAMYAB, ALI. "Preparation and evaluation of sulfided NiMo/γ-Al2O3 hydrotreating catalysts." Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190904.

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Four nickel-molybdenum catalysts were synthesized on gamma alumina with higher surface area and on NiMo catalyst was prepared using gamma alumina with lower surface area. Catalysts with higher-surface-area support were prepared by co-impregnation, sequential impregnation and adding phosphorous. Theses catalysts were calcined at 500  ͦC. Effect of higher calcination temperature was investigated by preparation of one catalyst calcined at 700 ͦC. Catalysts were thoroughly characterized via four characterization techniques. The hydrotreating activity of three catalysts was carried out in a micro reactor at high pressure and three different temperatures with Nynas vacuum middle distillate. Prior to the test, sulfiding was carried out to activate the catalysts. Hydrotreated-oil samples as products were analyzed to evaluate the activity and conversion of the catalyst. Also, the spent catalysts were characterized to evaluate the surface area characteristics and deactivation of catalysts. Addition of phosphorous to NiMo/gamma-Al2O3 improved the interaction between the metals and the support as well as reduced the coke formation as observed in scanning electron microscopy micrographs.
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Jofre, Jorge Benedito Freire. "Catalisadores de Ir-Ru/Al2O3 e Ru/Al2O3 aplicados em sistemas propulsores." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/97/97137/tde-03102012-112753/.

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Catalisadores de Ir/Al2O3, Ir-Ru/ Al2O3 e Ru/ Al2O3 com teores metálicos próximos a 30% em peso, foram preparados em vinte etapas de impregnação utilizando-se uma alumina sintetizada no LCP/INPE como suporte. Os catalisadores de Ir e Ir-Ru foram preparados a partir de soluções contendo precursores metálicos clorados pelo método de impregnação incipiente. Os catalisadores de Ru foram preparados a partir de dois precursores metálicos: um clorado e um precursor orgânico. Neste caso, o catalisador originado do precursor clorado foi preparado por impregnação incipiente, enquanto que o catalisador originado do precursor orgânico foi preparado pelo método de impregnação por excesso de volume. Todos os catalisadores foram caracterizados antes e depois dos testes em micropropulsor pelas técnicas: absorção atômica, para a determinação do teor metálico; fisissorção de nitrogênio, para determinações de área específica e distribuição do volume de mesoporos; quimissorção de hidrogênio e MET, para determinações da dispersão e do diâmetro médio das partículas metálicas (dQH e dMET). Os catalisadores foram testados na reação de decomposição de hidrazina em micropropulsor e comparados com o catalisador comercial Shell 405. Os resultados mostraram que os catalisadores contendo Ir apresentaram desempenho similar ao catalisador comercial e que os catalisadores de Ru não devem ser usados em partidas frias.
Ir/Al2O3, Ir-Ru/ Al2O3 and Ru/ Al2O3 catalysts with metallic loading of c. a. 30 %wt., were prepared in twenty impregnation steps using an alumina synthesized at LCP/INPE as support. The Ir and Ir-Ru catalysts were prepared from metallic chloride precursors solutions by incipient impregnation method. The Ru catalysts were prepared from two metallic different precursors: a chloride precursor and an organic precursor. In this case, the catalyst originated from the chloride precursor was prepared by the incipient impregnation method, while the catalyst originated from the organic precursor was prepared by volume excess impregnation method. All the catalysts were characterized before and after the microthruster tests by the following techniques: atomic absorption, for metallic content determination; nitrogen physiosorption, for specific area and mesoporous volume distribution; hydrogen chemisorption and TEM, for dispersion and metallic particles average diameter (dQH and dMET ). The catalysts were tested by the hydrazine decomposition reaction in microthruster and compared with commercial catalyst Shell 405. The results showed that the performance of Ir catalysts are similar to the commercial ones and the Ru catalysts should not be used in cold startups.
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Dessal, Caroline. "Influence de l'atmosphère réactive sur la stabilité structurale de catalyseurs Pt1 supporté et performances associées en oxydation de CO et photogénération d'hydrogène." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1305/document.

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Ce travail de thèse a consisté en l’étude de catalyseurs ultradispersés, composés de clusters nanométriques ou d’atomes isolés (single-atom catalysts, SACs) de métal, une nouvelle classe de catalyseurs faisant actuellement l’objet d’un engouement mondial. Les systèmes Pt/?-Al2O3 et Pt/TiO2 ont été préparés, caractérisés et testés en oxydation de CO et photogénération d’hydrogène, respectivement. Plusieurs méthodes d’imprégnation et de traitement thermique ont été comparées, notamment grâce à l’analyse de la dispersion du platine par microscopie électronique en transmission à balayage (STEM). Pour la préparation de SACs, notre choix s’est finalement porté sur l’imprégnation à humidité naissante d’une faible charge de précurseur Pt(NH3)4(NO3)2, suivie d’une calcination à l’air. L’étude des performances catalytiques et de l’évolution structurale des catalyseurs au cours des réactions a permis de montrer que les atomes isolés (cations) de platine étaient moins actifs que les clusters (réduits) pour les deux systèmes catalytiques étudiés. Dans le cas de Pt/?-Al2O3, des suivis par spectroscopie d’absorption X (XAS) operando en rayonnement synchrotron, spectroscopie infrarouge par réflexion diffuse (DRIFTS) operando et microscopie environnementale (E-STEM) ont montré la formation et la déstabilisation des SACs, cette dernière étant toutefois moindre en conditions oxydantes. En effet, l’oxygène stabilise le platine isolé via la formation de plusieurs liaisons Pt-O-Al comme montré par modélisation DFT, alors que la présence d’un composé réducteur (CO, H2) conduit à la formation de clusters, mobiles sur leur support. Ce travail met en évidence les limites possibles concernant la stabilisation et la mise en œuvre des SACs dans des réactions catalytiques impliquant des conditions réductrices
This PhD work is focused on the study of ultradispersed catalysts, composed of nanometer-sized clusters or isolated atoms (single-atom catalysts, SACs) of metal, a new class of catalysts which are currently the object of worldwide interest. The Pt/?-Al2O3 and Pt/TiO2 systems were prepared, characterized and evaluated for CO oxidation and hydrogen photogeneration, respectively.Several methods of impregnation and thermal treatment were compared, in particular through platinum dispersion analysis using scanning electron microscopy (STEM). For the preparation of SACs, our choice finally turned to the incipient wetness impregnation of Pt(NH3)4(NO3)2 precursor at low loading, followed by calcination in air.For the two catalytic systems of interest, the study of the performances and the structural evolution of the catalysts during the reactions shows that isolated Pt atoms (cations) are less active than their (reduced) cluster counterparts.In the case of Pt/?-Al2O3, operando X-ray absorption spectroscopy (XAS) using synchrotron radiation, operando diffuse reflectance infrared spectroscopy (DRIFTS), and environmental microscopy (E-STEM) allowed us to monitor the SAC formation and destabilization, the latter being however limited in oxidizing conditions. Indeed, the presence of oxygen stabilizes single Pt atoms via the formation of several Pt-O-Al bonds as shown by DFT modeling, whereas the presence of a reducing compound (CO, H2) leads to the formation of Pt clusters, mobile on their support.This work highlights the possible limitations in the stabilization and implementation of SACs for catalytic reactions involving reducing conditions
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Abreu, Amanda Jordão de. "Desenvolvimento e caracterização de catalisadores de níquel suportados em matrizes CeO2-ZrO2-Al2O3, CeO2-La2O3-Al2O3 e ZrO2-La2O3-Al2O3 avaliados para as reações de reforma do metano." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-24072012-135713/.

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A reforma do metano é um processo de grande interesse industrial para a produção de hidrogênio e de gás de síntese. Entre as reações de reforma do metano, destacam-se as reações de reforma a vapor e a reação com dióxido de carbono. O catalisador comumente utilizado nos processos e Ni/Al2O3. Porém, durante este processo, ocorre uma indesejada formação de depósitos carbonáceos na superfície do catalisador, os quais levam a sua destruição mecânica e, consequentemente, sua desativação. Por isso, uma das propriedades mais importantes de um bom catalisador para as reações de reforma do metano é a sua resistência a desativação. Entre as propostas para melhorar o desempenho do catalisador encontra-se a incorporação do óxido de cério junto ao suporte alumina. Catalisadores Ni/Al2O3 incorporados em soluções sólidas formadas por CeO2-ZrO2, ZrO2-La2O3 e CeO2-La2O3 foram preparados, caracterizados e submetidos a ensaios catalíticos nas reações de reforma a vapor e com dióxido de carbono e oxidação parcial do metano com objetivo de avaliar o efeito da adição da solução sólida ao suporte. Os suportes foram preparados pelo método da co-precipitação e os catalisadores foram obtidos pelo método de impregnação e calcinados a 500°C. Estes compostos foram caracterizados por Fisissorção de Nitrogênio, Difração de Raios X (DRX), Espectroscopia dispersiva de raios X (EDX), espectroscopia de na região do ultra violeta e do visível (UV-vis-NIR), Redução à Temperatura Programada (RTP), Espectrocopia RAMAN, Espectroscopia fotoeletrônica de Raios X (XPS), Espectroscopia de absorção de Raios X (XAS) e Análise termogravimétrica. Os ensaios catalíticos mostraram que a adição de solução sólida melhorou o desempenho do catalisador Ni/Al2O3 e, dentre todos os catalisadores avaliados, os melhores desempenhos obtidos foram com os catalisadores suportados em Ni/CeO2-La2O3-Al2O3.
Nowadays, the methane reforming is large interest industrial for the take advantage of these gas in production the hydrogen and synthesis gas (syngas). Among in the reactions of methane stand of the reactions steam reforming and carbon dioxide reforming of methane. The main catalysts uses in the methane reforming is Ni/Al2O3. However, the supported-nickel catalyst is susceptible to the deactivation or the destruction by coke deposition. The carbon dissolves in the nickel crystallite and its diffuses through the nickel, leading for formation of the carbon whiskers, which results in fragmentation of the catalyst. Modification of such catalysts, like incorporation of suitable promoters, is desirable to achieve reduction of the methane hydrogenolysis and/or promotion of the carbon gasification. Catalysts 5% Ni/Al2O3 supported on solid solutions formed by ZrO2-CeO2, La2O3 and CeO2-ZrO2-La2O3 were prepared, characterized and evalueted in reactions steam and carbon dioxide refoming and partial oxidation of methane with objetive the value effect loading solution solid in support. The supports were prepared by co-precipitation method and catalysts were prepared by impregnation method and calcined at 500°C. The supports and catalysts were characterized by Nitrogen Adsorption, method -rays diffraction (XRD), X-rays dispersive spectroscopy (XDS), spectroscopy in the region of the ultraviolet and the visible (UV-vis NIR) to and temperature programmed reduction (TPR), RAMAN Spectrocopy, X-ray absorption spectroscopy and Termogravimetric Analysis. After all the catalytic reactions check which the addition of solid solution is beneficial for Ni/Al2O3 catalysts and the best catalysts are Ni/CeO2-La2O3-Al2O3.
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5

Freire, Eleonora Maria Pereira de Luna. "Estudo das propriedades físico-químicas de sistemas Pd, Pd-Fe e Pd-Co suportados em CeO2/Al2O3." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266996.

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Orientadores: Antonio José Gomez Cobo, César Augusto Moraes de Abreu
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Os catalisadores à base de paládio apresentam particular interesse para o tratamento de gases de exaustão automotiva, notadamente no caso da combustão do etanol. O presente trabalho tem o objetivo de estudar as propriedades físico- químicas de catalisadores Pd - Fe e Pd - Co suportados em alumina modificada pelo óxido de cério. Para tanto, catalisadores modelo foram preparados através do método de impregnação por via úmida, empregando-se sais precursores à base de nitrato dos metais, e os suportes Al2O3, CeO2 e CeO2/Al2O3. Os catalisadores obtidos tiveram seus teores metálicos determinados por meio de espectrofotometria de absorção atômica, tendo sido caracterizados através de adsorção de nitrogênio (método B.E.T), espectroscopia no infravermelho, difração de raio-X, redução à temperatura programada. Os sistemas preparados foram avaliados pela reação catalítica de oxidação do etanol em fase gasosa em um microreator tubular de leito fixo, operando a pressão atmosférica e a temperatura de 3500 C. Os catalisadores preparados apresentam frações mássicas em torno de 2 % para o Pd, e de 1% para os aditivos Fe ou Co. A adição de Pd, Pd-Fe e Pd-Co aos suportes Al2O3 e CeO2/Al2O3 não levou a modificações, nos volumes dos poros e nas áreas superficiais específicas. Esses resultados mostram que a adição dos metais pouco influenciam nas características texturais. Enquanto para os bimetálicos suportados em céria, há a hipótese da existência de microporos apesar de ter ocorrido diminuições relativas das áreas superficiais específicas os volumes dos poros permanecem constantes. Na reação de oxidação do etanol, os resultados das análises cromatográficas levam a concluir que a introdução dos aditivos cobalto e ferro ao paládio provoca redução de eficiência na conversão do etanol para os sistemas CeO2 e CeO2/Al2O3. A adição do cobalto ao paládio na alumina aumenta a conversão e apresenta alto rendimento para a oxidação do etanol e o catalisador paládio suportado em céria apresenta conversão menor do que o Pd-Co sobre alumina porém rendimentos semelhantes
Abstract: Palladium based catalysts have been, applied at the treatment of the automotive gas exhaustion, particularly in the case of ethanol combustion. In this context, the actual work has the aim to study the physical and chemical properties of the Pd, Pd-Fe and Pd-Co catalysts supported in alumina, ceria and alumina modified by the cerium oxide. The wet impregnation method was used to develop the model catalysts. Precursor salts metal nitrates as well as the supports Al2O3, CeO2 and CeO2/Al2O3, were used for this purpose. The catalysts were characterised by the methods of BET-N2, infrared spectroscopy (I.R), X- ray diffraction (XRD) and reduction at programmed temperature (TPR). The contents of the metal impregnated in the catalysts was quantified by atomic absorption spectrophotometry (A.A.S.). A fixed-bed tubular microreactor was used to evaluate the performance of the catalysts in the oxidation of ethanol in gas phase, at the atmospheric pressure and temperature of 350o C. The mass fractions observed for the palladium catalysts and those that had Fe and Co as additive, were around 2% and 1%, respectively. The addition of the Pd, Pd-Fe and Pd-Co to the alumina support and alumina modified by cerium oxide does not prove modification into they capacity of the porous and surface areas. This results prove that the addition of metals has no power to the textural characteristics. Whereas the supported bimetallic system in ceria has the theory of the existence of micropores despite of a relative decrease of specific surface areas, the capacity of porous remains stable. The ethanol oxidation reaction, and the results of the cromatographicas analysis conclude that the introduction of cobalt and iron into the palladium decreases the efficacy of ethanol conversion into the CeO2 and CeO2/Al2O3 systems. The addition of cobalt into the palladium in alumina increases the conversion and introduces high performance for the ethanol oxidation and the palladium catalyst supported by cerium shows minor , conversion than to the cobalt-palladium upom alumina, but with the same results
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
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Zanotello, Tatiane Cristina. "Adição de fósforo (P) em catalisadores NiMo, suportados em γ-Al2O3, Al2O3/TiO2 e TiO2 - efeito na hidrodessulfurização do tiofeno." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/4108.

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Universidade Federal de Sao Carlos
Mo, NiMo or NiMoP HDS catalysts were supported on Al2O3, Al2O3-TiO2 or TiO2. These supports were synthesized via sol-gel and in the case o TiO2 it was used a commercial sample. The active phases were introduced by impregnation. Supports and catalysts in the oxide form were characterized by X-ray diffraction (XRD), diffuse reflectance UV-Vis spectroscopy (DRSUV-Vis), thermogravimetric analyses (TG), temperature-programmed reduction with H2 (TPR-H2), N2 adsorption/desorption, energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF), temperature-programmed desorption of NH3 (TPD-NH3), high resolution transmission electron microscopy (HRTEM) and evaluated at 300°C in the HDS of thiophene, used as a model molecule. Alumina presented a high specific surface area and meso/macroprous characteristics, allowing a high dispersion of the active phases, as was evidenced by XRD and DRSUV-VIS data. A HRTEM image of a NiMo/Al2O3 catalyst showed the presence of crystalline MoS2 whose activity was substantially promoted by the presence of Ni. The NiMo catalysts were active in the HDS of thiophene, however, the activity was enhanced significantly by the incorporation of P. This result corroborates the positive influence of P in the preparation of HDS catalysts. It was suggested that P must participate as promoter in the formation of the NiMoS phase during the sulfidation process of the Ni and Mo oxides. The supported NiMoP catalysts prepared in this work were more active than a commercial NiMoP/ Al2O3 catalyst, with this result validating the preparation procedures used here. The titania addition in the alumina framework led to NiMo catalysts possessing lower activity. That behavior was attributed to the formation of Ni and Mo sulfides without interaction diminishing the generation NiMoS phase, which is highly active in the HDS of sulfured organic compounds.
Catalisadores para hidrodessulfurização (HDS) contendo Mo, NiMo ou NiMo e o aditivo fósforo (P), foram suportados sobre Al2O3, Al2O3-TiO2 ou TiO2. A alumina e a alumina-titânia foram sintetizadas via sol-gel e, no caso da titânia pura, utilizada uma amostra comercial. A introdução dos sais precursores da fase ativa foi realizada via impregnação. Suportes e catalisadores na forma de óxidos foram caracterizados através de difração de raios X (DRX), espectroscopia por refletância difusa no ultravioleta visível (DRSUV-VIS), termogravimetria (TG), redução com hidrogênio à temperatura programada (RTP-H2), adsorção/dessorção de N2, espectroscopia de energia dispersiva de raios X (EDX), fluorescência de raios X (FRX), dessorção de amônia a temperatura programada (TPD-NH3), microscopia eletrônica de transmissão de alta resolução (HRTEM) e avaliados a 300⁰C na HDS do tiofeno. A alumina apresentou uma alta área superficial específica e características meso/macroporosa, possibilitando alta dispersão das fases ativas, conforme evidenciado por DRX e dados de DRSUV-VIS. A imagem de HRTEM do catalisador NiMo/Al2O3 mostrou a presença de MoS2 cuja atividade foi promovida substancialmente pela presença de Ni. Os catalisadores NiMo sobre os suportes utilizados foram ativos no HDS do tiofeno, entretanto, essa atividade foi melhorada pela incorporação de P. Esse resultado ratifica a influência positiva da utilização desse aditivo na preparação de catalisadores de HDS. O fósforo deve atuar como um promotor na formação de espécies NiMoS durante o processo de sulfetação dos óxidos de Mo e Ni. Os catalisadores NiMoP preparados neste trabalho apresentaram atividade específica superior à de um catalisador NiMoP/Al2O3 comercial, o que valida os procedimentos de preparação utilizados no trabalho. A adição de titânia na alumina durante a síntese sol-gel conduziu a catalisadores com menor atividade. Esse resultado foi atribuído à formação de sulfetos de Ni e Mo não interativos, com a consequente diminuição da formação da fase NiMoS de alta atividade no HDS de compostos organo-sulfurados.
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7

Roppertz, Andreas. "Struktur und Aktivität von Al2O3-geträgerten Eisenoxid-Katalysatoren zur Reinigung von Dieselabgas." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-216805.

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In der vorliegenden Arbeit werden Al2O3-geträgerte Eisenoxid-Katalysatoren auf ihre Eignung in der Nachbehandlung von Dieselabgasen getestet. Hierbei werden die Oxidationsreaktionen von Kohlenmonoxid, Propen, Stickstoffmonoxid sowie Ammoniak getestet. Weiterhin wird die Katalysatoraktivität bei der Stickoxidminderung nach dem SCR-Verfahren untersucht. Basierend auf einer detaillierten Charakterisierung wird eine Struktur-Aktivitäts-Korrelation entwickelt, auf deren Basis ein Verständnis für die Art der aktiven Zentren solcher Katalysatoren generiert wird. Zudem wird ein Modell entwickelt, mit Hilfe dessen die spezifische Aktivität der verschiedenen Typen an aktiven Zentren bewertet werden kann. Darüber hinaus wird in dieser Arbeit auf die Stickoxidminderung nach dem SCR-Verfahren fokussiert, was die Untersuchungen des Reaktionsmechanismus sowie die Struktur-Aktivitäts-Korrelation an hydrothermal gealterten Katalysatoren beinhaltet.
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8

Andrade, Lidiane Maria de. "Reforma a vapor e oxidativa de etanol para a produção de hidrogênio utilizando catalisadores de ródio suportados em g-Al2O3, CeO2 e CeO2-g-Al2O3." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-14092007-142615/.

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Pesquisas realizadas em todo o mundo exploram a possibilidade de utilizar o hidrogênio como combustível para a geração de energia, já que ele produz a chamada \"energia limpa\". O hidrogênio pode ser obtido a partir das reações de reforma de etanol, fonte renovável, em contraste com o clássico processo de obtenção a partir de derivados de petróleo. Desta forma, há um crescente interesse em pesquisa e desenvolvimento de catalisadores eficientes para gerar hidrogênio. Assim, no presente trabalho foram estudados catalisadores de ródio contendo 0,5; 1 e 3% (m/m) suportados em CeO2, Al2O3 e 20%CeO2- Al2O3 nas reações de reforma a vapor de etanol (RVE) e reforma oxidativa de etanol (ROE) visando a geração de hidrogênio. As amostras foram preparadas pelo método de impregnação úmida e caracterizadas por difração de Raios-X (XRD), área superficial específica - método B.E.T., espectroscopia dispersiva em emissão de Raios-X (EDX), espectroscopia de fotoelétrons excitada por Raios-X (XPS), espectroscopia na região do ultra-violeta e do visível (UV-vis- NIR) e redução à temperatura programada (RTP-H2). Os ensaios catalíticos, realizados entre 400 e 600ºC, mostraram altas conversões de etanol para todos os catalisadores. As maiores produções de H2, a partir das reações de RVE e ROE, foram obtidas à 600ºC com os catalisadores Rh/CeO2 e Rh/20%CeO2-Al2O3. Foi observado que a adição de oxigênio proporcionou um aumento na produção de H2, bem como na razão CO2/CO e nas deposições de carbono.
The researches made in the world explore the possibility in the use of hydrogen like a fuel for energy generation, since it produces the called \"clean energy\". The hydrogen can be obtained through of the ethanol reforming reaction, i.e. renewable source, in contrast with the classical process for obtaining from petroleum derivates. In this way, there is a crescent interest in research and development of efficient catalysts in order to obtain hydrogen. Thus, in this work were studied the rodium catalysts with 0,5; 1 e 3% (w/w) supported on CeO2, Al2O3 e 20%CeO2-Al2O3 for the ethanol steam reforming (ESR) and oxidative reforming (EOR) reactions aiming to the hydrogen generation. The samples were prepared by wet impregnation method and characterized by X-ray diffraction (XRD), specific superficial area - BET method, energy dipersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy (UVvis), and temperature-programmed reduction (TPR-H2). In according to the catalytic tests, performed between 400 and 600ºC, it was obtained higher ethanol conversion values for all catalysts. The highest H2 yield it was obtained at 600ºC, with the Rh/CeO2 e Rh/20%CeO2-Al2O3 catalysts. It was observed that the addition of oxygen caused an increase in H2 production, as well as, in the CO2/CO ratio and in the carbon deposition.
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Barreto, Rubens Santos. "Efeito da concentração de irídio sobre as propriedades de catalisadores do tipo Pt-Ge-Ir/Al2O3." Programa de Pós-Graduação em Química da UFBA, 2008. http://www.repositorio.ufba.br/ri/handle/ri/10012.

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Neste trabalho, foi estudado o efeito do conteúdo de irídio na atividade, seletividade e estabilidade de catalisadores de platina, irídio e germânio suportados em alumina, destinados à reforma catalítica de nafta de petróleo. As amostras foram preparadas por impregnação dos sais metálicos (ácido hexacloroplatínico, ácido hexacloroirídico e cloreto de germânio) na g-alumina, de modo a obter 0,3 % de platina e de germânio e teores vairados de irídio (0,03; 0,06; 0,09 e 0,15 %). Os sólidos obtidos foram caracterizados por redução termoprogramada, espectroscopia no infravermelho com transformada de Fourier de monóxido de carbono adsorvido, dessorção à temperatura programada de piridina, desidrogenação de cicloexano e isomerização de npentano, usadas para avaliar as funções metálica e ácida, respectivamente. O desempenho foi avaliado na reforma de n-octano. Os catalisadores usados nessa reação foram analisados por oxidação termoprogramada. Os resultados mostraram que o irídio catalisa a redução da platina, enquanto o germânio exerce um efeito inibidor; esses efeitos dependem da quantidade de irídio nos sólidos, devido às diferentes interações entre os metais e com o suporte. Ambos os metais modificam eletronicamente a platina, tornando-a mais rica (irídio) ou mais deficiente (germânio) em elétrons. Entretanto, nos catalisadores trimetálicos, o efeito do germânio sobre a platina só se torna significativo em concentrações mais elevadas de irídio (0,15 %), que promove a redução do germânio, gerando sólidos com espécies de platina em diferentes estados eletrônicos. A presença do germânio diminui a concentração de sítios ácidos fracos e aumenta aqueles de acidez moderada e forte, enquanto o irídio provoca alterações na concentração de sítios de diferentes forças ácidas, dependendo do seu teor nos sólidos. A atividade catalítica dos sítios metálicos na desidrogenação do cicloexano diminui devido ao germânio enquanto o irídio (em teores superiores a 0,03 %) causa um aumento, devido à sua atividade dedidrogenante; este efeito aumenta com o teor de irídio nos sólidos. Nos catalisadores trimetálicos a atividade dos sítios metálicos é mais baixa que no sistema monometálico de platina, devido ao efeito simultâneo dos dois metais, que podem estar formando ligas com a platina e/ou encobrindo seus sítios ativos diminuindo sua atividade de desidrogenação. A adição de irídio e de germânio a catalisadores de platina suportada em alumina aumenta a sua atividade na isomerização do n-pentano e diminui a atividade de hidrogenólise. Nos catalisadores trimetálicos, a seletividade a compostos aromáticos é inferior àquela dos sistemas bimetálicos e o orto-xileno é o isômero mais favorecido. O germânio aumenta a estabilidade dos catalisadores enquanto o irídio exerce um efeito inverso. A produção de compostos aromáticos diminui com o aumento do teor de irídio no catalisador, enquanto um comportamento inverso é observado com relação à seletividade a produtos isômeros. A razão entre as seletividades a compostos isômeros e aromáticos cresce com o conteúdo de irídio, de modo que se um reformado mais rico em compostos aromáticos é desejado, deve-se usar um catalisador com baixos teores de irídio. Por outro lado, uma composição com concentração de irídio mais alta produz um reformado mais rico em compostos isômeros e, portanto, mais adequado ao uso como combustível.
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10

Takahashi, Masaru. "Solvothermal synthesis of Ga2O3-Al2O3 catalysts and their performance for selective catalytic reduction of NO with methane." 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/136136.

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Books on the topic "Al2O3 catalysts"

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T. R. H. E. Burm. Carbon monoxide hydrogenation over Ru-Cu/Al2O3 catalysts. Manchester: UMIST, 1996.

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Zemicael, F. W. Structure sensitivity of model copper catalysts and Cu/ZnO/Al2O3 methanol synthesis and low temperature shift catalysis. Manchester: UMIST, 1996.

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Elliott, Andrew J. Characterisation of the role of magnesium promotion when incorporated into industrial Cu/ZnO/Al2O3 methanol synthesis catalysts. Manchester: UMIST, 1997.

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Zemicael, F. W. Structure/activity relationship of cu/zno/al2o3 methanol synthesis catalysis. Manchester: UMIST, 1993.

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Chiri, J. M. Methanol synthesis on a Mg-doped Cu/ZnO/Al2O3 catalyst. Manchester: UMIST, 1997.

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Isaac, J. Structure/activity relationship of Cu/ZnO/Al203 methanol synthesis catalysts. Manchester: UMIST, 1997.

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Auger, Bruno. Effect of magnesium doping on the catalytic behaviour of methanol synthesis catalyst Cu/ZnO/Al2O3. Manchester: UMIST, 1996.

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Book chapters on the topic "Al2O3 catalysts"

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Shinoki, Toshio, Yuichi Sono, Kenji Ota, Jiro Funaki, and Katsuya Hirata. "Hydrogen Production Using Ethanol-Steam-Reforming Reactor with Cu/ZnO/Al2O3 and Ru/Al2O3 Catalysts." In Challenges of Power Engineering and Environment, 986–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-76694-0_183.

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Cherif, Ali, Rachid Nebbali, and Lyes Nasseri. "Optimization of the Ni/Al2O3 and Pt/Al2O3 Catalysts Load in Autothermal Steam Methane Reforming." In Springer Proceedings in Energy, 145–50. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6595-3_20.

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Gutiérrez-Alejandre, Aída, and Jorge Ramírez. "Molecular Structures of WO3/Al2O3-TiO2 Catalysts Under Controlled Environment." In Emerging Fields in Sol-Gel Science and Technology, 238–45. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4615-0449-8_26.

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Jacobs, J. P., G. C. van Leerdam, and H. H. Brongersma. "Study of the Surface Structure of V2O5/γ-Al2O3 Catalysts by LEIS." In Fundamental Aspects of Heterogeneous Catalysis Studied by Particle Beams, 399–403. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-5964-7_29.

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Sudhakar, Chakka, NazeerA Bhore, KennethB Bischoff, WilliamH Manogue, and G. Alex Mills. "Molybdena Enhanced Rh/Al2O3 Catalysts." In Studies in Surface Science and Catalysis, 115–24. Elsevier, 1988. http://dx.doi.org/10.1016/s0167-2991(09)60648-0.

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Huirache-Acuña, Rafael, Gabriel Alonso-Nuñez, Eric M. Rivera-Muñoz, Omar Gutierrez, and Barbara Pawelec. "Trimetallic Sulfide Catalysts for Hydrodesulfurization." In Applying Nanotechnology to the Desulfurization Process in Petroleum Engineering, 240–62. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9545-0.ch008.

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The more stringent environmental regulations enacted throughout the world have increased the need of more active hydrotreating (HDT) catalysts, in the petroleum refining industry. Usually, the catalysts used for diesel oil hydrotreatment are ?-Al2O3 supported molybdenum or tungsten sulfides promoted with cobalt or nickel. Current strategies for the design of novel HDS catalysts often include variations in the support formulation, catalyst preparation method and active phase formulation. In this sense, the new generations of catalysts, such as NEBULA®, are based on a totally different concept of bulk-like. In this chapter, we present recent research related to the synthesis, characterization and performance of trimetallic sulfide nanocatalysts for hydrodesulfurization. The present chapter analyses the state of art of the ternary sulfide hydrotreating catalysts.
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Rashid, K. K. Abdul, K. V. Lakshmi, M. Nandan, K. O. Xavier, and B. Sen. "Pt/Al2O3 catalysts for benzene hydrogenation." In Recent Advances In Basic and Applied Aspects of Industrial Catalysis, Proceedings of 13th National Symposium and Silver Jubilee Symposium of Catalysis of India, 829–34. Elsevier, 1998. http://dx.doi.org/10.1016/s0167-2991(98)80366-2.

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Abderrahim, H., and D. Duprez. "Surface Diffusion of Oxygen in Rh/Al2O3 and Pt/Al2O3 Catalysts." In Catalysis and Automotive Pollution Control, Proceedings of the First International Symposium (CAPOC I), 359–68. Elsevier, 1987. http://dx.doi.org/10.1016/s0167-2991(09)60435-3.

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Angelidis, T. N., and V. Tzitzios. "A comparative kinetic study of CH4 oxidation by NiO/Al2O3, Pt/Al2O3 and NiO-Pt/Al2O3 catalysts." In Studies in Surface Science and Catalysis, 341–48. Elsevier, 1999. http://dx.doi.org/10.1016/s0167-2991(99)80165-7.

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Paulis, M., N. Burgos, M. Montes, C. López-Cartes, J. M. Gatica, and J. J. Calvino. "Chlorine mobility in Pt/Al2O3 and Pt/Al2O3/Al complete oxidation catalysts." In Spillover and Mobility of Species on Solid Surfaces, 413–20. Elsevier, 2001. http://dx.doi.org/10.1016/s0167-2991(01)80056-2.

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Conference papers on the topic "Al2O3 catalysts"

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Navarrete Rodriguez, Luisa Fernanda, Inés Reyero, Oihane Sanz, Siby Gárces, Fernando Bimbela, Mario Montes, and Luis María Gandía. "CO2 methanation over Ni/La-Al2O3 catalysts." In 14th Mediterranean Congress of Chemical Engineering (MeCCE14). Grupo Pacífico, 2021. http://dx.doi.org/10.48158/mecce-14.dg.11.02.

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Lim, Emmanuel, Teeravit Visutipol, Wen Peng, and Nico Hotz. "Flame-Made CuO/ZnO/Al2O3 Catalyst for Methanol Steam Reforming." In ASME 2013 7th International Conference on Energy Sustainability collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/es2013-18388.

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In the present study, a catalyst produced by flame spray pyrolysis (FSP) was evaluated for its ability to produce hydrogen-rich gas mixtures. Catalyst particles fabricated by a novel flame spray pyrolysis method resulting in a highly active catalyst with high surface-to-volume ratio were compared to a commercially produced catalyst (BASF F3-01). Both catalysts consisted of CuO/ZnO/Al2O3 of identical composition (CuO 40wt%, ZnO 40wt%, Al2O3 20wt%). Reaction temperatures between 220 and 295 °C, methanol-water inlet flow rates between 2 and 50 μl/min, and reactor masses between 25 and 100 mg were tested for their effect on methanol conversion and the production of undesired carbon monoxide. 100% methanol conversion can be easily achieved within the operational conditions mentioned for this flame-made catalyst — at reactor temperatures of 255 °C (achievable with non-concentrating solar collectors) more than 80% methanol conversion can be reached for methanol-water inlet flow rates as high as 10 μl/min. The FSP catalyst demonstrates similar catalytic abilities as the BASF, produces a consistent gas composition and produces lower overall CO production. Furthermore, the FSP catalyst demonstrates a better suitability to fuel cell use through its higher resistance to degradation and smaller production of carbon monoxide over long-term use. In the present study, the merits of using flame spray pyrolysis to produce CuO/ZnO/Al2O3 methanol steam reforming catalysts are examined, and directly compared to catalysts that are commercially produced in bulk pellet form, and then ground and sieved. The comparison is performed from several different perspectives: catalytic activity and CO production at various temperatures and fuel inlet flow rates; surface and structure characteristics are determined via scanning electron and transmission electron microscopy; surface area characteristics are determined via BET tests.
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Quanxiang Li, Weimin Kang, Bowen Cheng, Yuanlin Ren, and Xue Bai. "Fabrication of the SnO2/Al2O3 catalysts through electrospinning." In 2010 IEEE 3rd International Nanoelectronics Conference (INEC). IEEE, 2010. http://dx.doi.org/10.1109/inec.2010.5424991.

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Nepomnyashchiy, A. A., E. A. Buluchevskiy, T. R. Karpova, and A. V. Lavrenov. "Hydrodeoxygenation of sunflower oil over NiMoS/MoO3-Al2O3 and NiMoS/P2O5-Al2O3 catalysts." In 21ST CENTURY: CHEMISTRY TO LIFE. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5122951.

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Huang, Chih-Yung, Chun-Hung Lin, Chung-Yang Chou, and Chin-Chia Su. "Experimental Studies of the Performance of a Small Reformer for Hydrogen Generation." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97045.

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This paper presents the experimental studies of the performance of a small reformer for hydrogen generation from water solution of methanol. An electric heater was built around the reactor unit to supply the energy for the endothermal reaction between methanol and steam. The parameters under studied were the temperature of the catalytic reaction (T), the mass flow rate of methanol solution (m˙), steam-to-methanol ratio (α), and the length (L) and number of cells (N) of the catalyst carrier, while the catalysts used were CuO-ZnO-Al2O3, CuO-ZnO-Al2O3-Pt-Rh, and Pt-Rh. The test results show that for all conditions both of the conversion and yield rates of hydrogen increase with increasing length and number of cells of the catalyst carrier. However, such increases become gradual in the high ranges of L and N. For the catalyst CuO-ZnO-Al2O3-Pt-Rh with N = 300 cells per square inch, L = 105mm, α = 1.9, and m˙ = 0.064 mole/min, the conversion rate may be as high as 99.9%. On the other hand, both of the conversion and yield rates decrease with increasing ratio of steam to methanol in the reactant. The decreases are more apparent at high temperature. When the mass flow rate of the methanol solution is increased, the conversion rate decreases. Such a decrease is more distinct in the medium range of methanol flow rate. On the other hand, the yield rate of hydrogen increases with the flow rate of methanol solution, especially at high temperature. For all of the three catalysts tested, both of the conversion and yield rates increase with reaction temperature, except for catalyst CuO-ZnO-Al2O3 at high temperature. Although catalyst CuO-ZnO-Al2O3-Pt-Rh shows no high-temperature deterioration, its performance is much poorer than that of catalyst CuO-ZnO-Al2O3 at low to medium temperatures. The difference in the performance between these two catalysts may be as high as 50%. By arranging a turbulence inducer located at the upstream side of the catalyst carrier, both of the conversion and yield rates can be increased significantly.
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Wu, Quanwen, Wenhua Luo, Daqiao Meng, Jinchun Bao, and Jingwen Ba. "High Efficient Detritiation Catalysts for Fusion Safety." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81269.

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Tritium is indispensable to the fusion reactor engineering, and it must be seriously defended because of its radioactivity and permeability. The method of catalytic oxidation and absorption is the most widely used process for tritium cleanup so far, in which detritiation catalyst is of great importance. The poor stability caused by the agglomeration of noble metal limits the life of detritiation catalysts. Here, Anti–Ostwald Ripening is used to prepare single-atom detritiation catalysts S-Pt/Ce0.7Zr0.3O2 for tritium (HT, DT and T2) oxidation. Single-atom dispersed Pt ensures the catalytic activity and decreased the economic cost. The strong metal-support interaction (SMSI) keeps Pt from aggregating, thus increases the working life of catalyst. And Pd based catalyst supported by a cation ordered κ-Ce2Zr2O8 is prepared for tritiated methane (CH4-xTx) oxidation. Tritiated methane is mostly oxidized by Pd/κ-Ce2Zr2O8 at about 450 °C, which is at least 50 °C lower than normal catalysts (such as Pd/Al2O3).
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Hotz, Nico. "Flame-Made Catalyst for Bio-Methanol Steam Reforming." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65425.

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In the present study, a catalyst produced by flame spray pyrolysis (FSP) was evaluated for its ability to produce hydrogen-rich gas mixtures. Catalyst particles fabricated by a novel flame spray pyrolysis method resulting in a highly active catalyst with high surface-to-volume ratio were compared to a commercially produced catalyst (BASF F3-01). Both catalysts consisted of CuO/ZnO/Al2O3 of identical composition (CuO 40wt%, ZnO 40wt%, Al2O3 20wt%). Reaction temperatures between 220 and 295 °C, methanol-water inlet flow rates between 2 and 50 μl/min, and reactor masses between 25 and 100 mg were tested for their effect on methanol conversion and the production of undesired carbon monoxide. 100% methanol conversion can be easily achieved within the operational conditions mentioned for this flame-made catalyst — at reactor temperatures of 255 °C (achievable with non-concentrating solar collectors) more than 80% methanol conversion can be reached for methanol-water inlet flow rates as high as 10 μl/min. The FSP catalyst demonstrates similar catalytic abilities as the BASF, produces a consistent gas composition and produces lower overall CO production. Furthermore, the FSP catalyst demonstrates a better suitability to fuel cell use through its higher resistance to degradation and smaller production of carbon monoxide over long-term use. In the present study, the merits of using flame spray pyrolysis to produce CuO/ZnO/Al2O3 methanol steam reforming catalysts are examined, and directly compared to catalysts that are commercially produced in bulk pellet form, and then ground and sieved. The comparison is performed from several different perspectives: catalytic activity and CO production at various temperatures and fuel inlet flow rates; surface and structure characteristics are determined via scanning electron and transmission electron microscopy; surface area characteristics are determined via Brunauer-Emmett-Teller (BET) tests.
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Berry, David A., Dushyant Shekhawat, Todd H. Gardner, Maria Salazar, Daniel J. Haynes, and James J. Spivey. "Support Effects for Pt and Rh-Based Catalysts for Partial Oxidation of n-Tetradecane." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97265.

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Catalytic partial oxidation (CPOX) of liquid fuels is an attractive option for producing a hydrogen-rich gas stream for fuel cell applications. However, the high sulfur content along with aromatic compounds present in liquid fuels may deactivate reforming catalysts. Deactivation of these catalysts by carbon deposition and sulfur poisoning is a key technical challenge. The relationship between catalyst supports and deactivation have been studied here for three catalysts (Rh/Ce0.5Zr0.5O2, Pt/Ce0.5Zr0.5O2, and Pt/Al2O3) in a fixed bed catalytic reactor using a mixture of n-tetradecane, 1-methylnaphthalene, and dibenzothiophene to simulate logistic fuels. Carbon production during CPOX reforming was directly related to olefin formation. Olefins, which are known coke precursors, were observed on the Pt catalysts during CPOX of n-tetradecane with no sulfur (particularly from Pt/Al2O3), but not on Rh/Ce0.5Zr0.5O2. For the Rh/Ce0.5Zr0.5O2, yields of H2 and CO dropped to a stationary level after the introduction of sulfur-containing feed (1000 ppm sulfur) or aromatic-containing feed (5 wt%), however, the catalyst activity was restored after removing the sulfur or aromatics from the feed. For the Pt catalysts, H2 and CO yields dropped continuously over time in the presence of sulfur or aromatics in feed. The superior performance of Rh/Ce0.5Zr0.5O2 can be attributed to the higher oxygen-ion conductivity of the Ce0.5Zr0.5O2 support as well as the activity of the Rh sites.
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Sricharoenchaikul, Viboon, Sildara Thassanaprichayanont, and Duangduen Atong. "Investigation of 64%Ni on SiO2-Al2O3 Catalyst as Tar Removal Catalysts for Biomass Gasification." In ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90383.

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Biomass gasification is a recognized process that may generate synthesis gas (H2+CO) from renewable resources. During gasification, a complex mixture of condensable hydrocarbons or tar compounds form; this can interfere with downstream utilization technologies and also reduce gasification efficiency. Catalytic tar conversion of these compounds to additional product gas is technically and economically interesting approach to reduce or to eliminate tar in product stream. In this paper, 64% Ni on SiO2-Al2O3 catalyst was used as tar removal catalyst. The catalytic performance of this catalyst was evaluated by the conversion of benzene as a model of tar component using a fixed bed reactor. The process variables including reaction temperature 500, 600 and 700°C, Amount of steam added in the cracking and reforming reactions of 1.44 and 2.88 vol.%. The reactor effluent was analyzed by on-line FTIR for CO, CO2, CH4, and other hydrocarbons. Part of the gas product was collected in sample vials for concurrent analysis by GC. The results indicated that the highest conversion of benzene and superior ratio of [CO] to [CO2] may be obtained from at 700°C reaction temperature and 1.44% volume of H2O where 91.2% conversion and ratio of 18.1 may be obtained, respectively. Generally, the distribution of produced gas was greater than the data predicted by equilibrium calculation according to water-gas shift reaction.
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Gengembre, Eric, Stephane Mary, Charles Kappenstein, Stephane Balcon, and Sylvie Rossignol. "Aging of Ir/Al2O3 catalysts for the decomposition of hydrazine." In 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1998. http://dx.doi.org/10.2514/6.1998-3666.

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Reports on the topic "Al2O3 catalysts"

1

Minja, R. J. A., and M. Ternan. Effect of H-mordenite zeolite as a component in Co-Mo-Al203 hydroprocessing catalysts used for the conversion of Boscan heavy oil. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1989. http://dx.doi.org/10.4095/304445.

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Wilson, M. F. Use of sepiolite/y-Al203 supports for preparation of Co-Mo and Ni-Mo hydrotreating catalysts applications for sulphur and nitrogen removal from Syncrude gas oils. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1989. http://dx.doi.org/10.4095/304419.

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