Transient kinetic model of CO oxidation over a nanostructured Cu0.1Ce0.9O2− catalyst

Sedmak, Gregor; Hočevar, Stanko; Levec, Janez

doi:10.1016/j.jcat.2003.10.006

Cited by 150 publications

(111 citation statements)

References 48 publications

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“…As concerns the kinetics, several models have been proposed for the PROX reaction over CuO xCeO 2 [25][26][27][28][29][30][31][32]. The formulation of adequate kinetic models is a key step on designing and scaling up of PROX units [33], thus being fundamental for the practical applications of this H 2 cleaning technology.…”

Section:  mentioning

confidence: 99%

Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)

Laguna

Hernández

Arzamendi

et al. 2014

Fuel

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Hydrogen produced from the conversion of hydrocarbons or alcohols contains variable amounts of CO that should be removed for some applications such as feeding lowtemperature polymer electrolyte membrane fuel cells (PEMFCs). The CO preferential oxidation reaction (PROX) is particularly well-suited for hydrogen purification for portable and on-board applications. In this work, the synthesis and characterization by XRF, BET, XRD, Raman spectroscopy and H 2 -TPR of a gold catalyst supported on a copper-cerium mixed oxide (AuCeCu) for the PROX reaction are presented. The comparison of this catalyst with the copper-cerium mixed oxide (CeCu) revealed that the experimental procedure used for the deposition of gold gave rise to the loss of reducible material by copper lixiviation. However, the AuCeCu solid was more active for CO oxidation at low temperature. A kinetic study has been carried over the AuCeCu catalyst for the PROX reaction and compared with that of the CeCu catalyst. The main difference between the models affected the contribution of the CO adsorption term. This fact may be related to the surface electronic activity produced by the interaction of the cationic species in the AuCeCu solid, able to create more active sites for the CO adsorption and activation in the presence of gold.

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Section:  mentioning

confidence: 99%

Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)

Laguna

Hernández

Arzamendi

et al. 2014

Fuel

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“…[41] In this mechanism, CO (or H 2 ) molecules are adsorbed onto Cu cations at the catalyst surface, at which point surface oxygen is abstracted to yield the reaction product CO 2 (or H 2 O). The reduced catalyst surface can then be re-oxidized by either lattice or gaseous oxygen.…”

Section: Full Papermentioning

confidence: 99%

Flame‐Synthesized Ceria‐Supported Copper Dimers for Preferential Oxidation of CO

Kydd¹,

Teoh²,

Wong³

et al. 2009

Adv Funct Materials

122

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Rapid synthesis of CuCeO2 catalysts by flame spray pyrolysis produces highly active Cu dimer morphologies without the need for additional catalyst pretreatment. The active Cu component is enriched onto the CeO2 surface at concentrations higher than the nominal loading with no evidence of amorphous or crystalline CuO phase. Increasing the Cu content results in a morphological transition from isolated Cu monomers to oxygen‐bridged dimers and an associated increase in oxygen vacancy concentration. Dimer‐containing CuCeO2 catalysts display high levels of activity and selectivity in the low‐temperature preferential oxidation of CO. Experimental measurements and simulations suggest that the geometry of the dimer presents a comparatively ionic CuO bond at the catalyst surface. Further studies indicate that these ionic dimer species promote preferential CO oxidation at lower temperatures than observed for monomeric Cu species. This is the first report to explicitly propose and demonstrate that the structural distortion associated with the formation of Cu dimers directly induces increased bond ionicity at the catalyst surface and that these changes are responsible for improved catalytic activity.

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“…[27][28][29] Relacionando as temperaturas de redução referentes ao CuO com o teor mássico do metal em cada amostra, verifica-se que o aumento do teor de cobre provoca um deslocamento dos picos, embora pequeno, para menores temperaturas. Isso acontece com todos os catalisadores suportados.…”

Section: Redução a Temperatura Programadaunclassified

Estudo da reação de oxidação preferencial do co sobre o sistema CuO/CeO2-TiO2

Maciel

Assaf

2010

Quím. Nova

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Recebido em 24/2/10; aceito em 21/6/10; publicado na web em 17/9/10 CO PREFERENTIAL OXIDATION ON CuO/CeO 2 -TiO 2 SYSTEM. Cu catalysts supported on CeO 2 , TiO 2 and CeO 2 /TiO 2 were prepared by precipitation method and used for preferential oxidation of carbon monoxide contained in a hydrogen flow generated by methane steam reforming. The samples were characterized by XRD, BET and TPR techniques. The catalytic properties were studied in the 50-330ºC range by using a quartz micro-reactor vertically positioned on an electrical furnace. The results showed that the small copper particles generated with the lower metal content are the most easily reducible and give the best catalytic performance. In respect of support effect, the strong metal-support interaction and the redox characteristics of the CuO x -CeO 2 series resulted in the best catalytic results, especially with the sample with 1% copper content.Keywords: PROX-CO; copper; ceria. INTRODUÇÃOEstudos recentes relacionados com a tecnologia de células a combustível, especialmente aqueles envolvendo membranas poliméricas de troca iônica (PEMFC), têm estimulado o interesse pela reação de oxidação preferencial do monóxido de carbono (PROX-CO). Uma vez que as células PEMFC utilizam como fonte de energia o hidrogênio com elevada pureza, a reação de PROX-CO apresenta-se como um meio de purificar o hidrogênio produzido pelas reações de reforma do metano. 1-10O método convencional de produção de hidrogênio combina as reações de reforma a vapor do metano com a reação de deslocamento gás-água (WGS -water gas shift reaction), e os gases gerados apresentam a seguinte composição aproximada: 45% H 2 , 25% CO 2 , 10% H 2 O, 20% N 2 e 0,5-1% CO.1,2 Essa quantidade de CO presente no gás de reforma precisa ser removida devido a efeitos adversos que provoca no anodo das células PEMFC, ocasionando a desativação do eletrocatalisador de Pt que está depositado sobre uma camada difusora à base de carbono e teflon (PTFE). Assim, é necessária a remoção do CO, reduzindo seus níveis para valores menores que 10 ppm.1 Para alcançar esse nível de concentração, alguns caminhos são estudados: metanação catalítica, separação por membrana de Pd e oxidação preferencial do CO (PROX-CO).1,11 Destas, a PROX é a que oferece menor custo na redução dos níveis de CO sem o consumo excessivo de hidrogênio. 1Juntamente com a PROX-CO (Equação 1), a reação indesejada de oxidação do hidrogênio (Equação 2) pode ocorrer, diminuindo a eficiência do processo.(1)O catalisador convencional para a PROX-CO é Pt/g-Al 2 O 3 , porém diferentes tipos de catalisadores mostraram ser eficientes para a reação. Estes podem envolver fases ativas de metais nobres suportados, como platina e ouro, ou ainda metais não-nobres, como o cobre suportado em óxidos. 1,2Os catalisadores de metais nobres exibem boa atividade catalí-tica em temperaturas entre 150-250 ºC mas, além de apresentarem um alto custo, no geral, são pouco seletivos.3 Por outro lado, alguns catalisadores de metais não nobres suportados em óxidos têm se mostrado efic...

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Transient kinetic model of CO oxidation over a nanostructured Cu0.1Ce0.9O2− catalyst

Cited by 150 publications

References 48 publications

Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)

Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)

Flame‐Synthesized Ceria‐Supported Copper Dimers for Preferential Oxidation of CO

Estudo da reação de oxidação preferencial do co sobre o sistema CuO/CeO2-TiO2

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