Preferential oxidation properties of CO in excess hydrogen over CuO-CeO2 catalyst prepared by hydrothermal method

Zhu, Pengfei; Li, Jing; Zuo, Shufeng; Zhou, Renxian

doi:10.1016/j.apsusc.2008.08.033

Cited by 93 publications

(53 citation statements)

References 44 publications

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“…Likewise, the abovementioned diffraction peaks are also found over the Cu 0.2 Mn 0.1 Ce 0.7 O x catalyst, which indicates that Mn species may affect the dispersion of copper oxides at relatively high Cu loading and probably lead to the aggregation of copper species on the surface of cerium oxide. Aggregation of copper species on the surface of cerium oxide is disadvantageous to chlorobenzene combustion as part of the surface active sites are covered by the bulk CuO particles [50]. The diffraction peaks are broadened in Cu a Mn 0.3-a Ce 0.7 O x catalysts, indicating the occurrence of more defective cerianite lattice and smaller crystallite size.…”

Section: Deactivation Of the Cumnceo X Catalystsmentioning

confidence: 93%

“…8 shows the Mn 2p 3/2 region spectra of all Mn-containing mixed metal oxides. Mn ions in 2+ (639.9 eV), 3+ (641.0 eV), and 4+ (642.3 eV) oxidation states in cerium-free materials has been reported in the literature [50]. Herein, the Mn 2p 3/2 region is presented as deconvoluted into all its components and its relative ion ratios are listed in Table 3.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

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Catalytic behavior and synergistic effect of nanostructured mesoporous CuO-MnOx-CeO2 catalysts for chlorobenzene destruction

Shen

et al. 2014

Applied Surface Science

101

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a b s t r a c tMesoporous CuO-MnO x -CeO 2 composite metal oxides with different copper and manganese loadings were prepared by a urea-assistant hydrothermal method, and were further adopted for the complete catalytic combustion of chlorobenzene. The effects of reaction conditions such as inlet reagent concentration and water feed concentration on chlorobenzene combustion were also studied. The structure and textural properties of the synthesized catalysts were characterized via the XRD, N 2 adsorption/desorption, FE-SEM, TEM, H 2 -TPR, O 2 -TPD, and XPS techniques. The characterization results reveal that the presence of a small amount of Mn species can facilitate the incorporation of Cu and Mn ions into ceria lattice to form Cu-Mn-Ce-O solid solution. The synergistic effect of Cu and Mn species can reduce the redox potential of the composite catalysts, and produce large amounts of oxygen vacancies in the interface of CuO x , MnO x , and CeO 2 oxides. The catalyst with Cu/Mn atomic ratio of 1/1 exhibits the best chlorobenzene elimination capability, oxidizing about 95% of the inlet chlorobenzene at 264• C with CO 2 selectivity higher than 99.5%. The concentration and mobility of the chemically adsorbed oxygen are vital for the effective removal of surface Cl species, which inhibits the dissociation of oxygen molecules and decreases the reducibility of the copper and manganese species. It can be rationally concluded that the superior catalytic performance and durability of the mesoporous CuO-MnO x -CeO 2 composite oxides are primarily attributed to the higher surface oxygen concentration and better active oxygen mobility.

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Section: Deactivation Of the Cumnceo X Catalystsmentioning

confidence: 93%

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

Catalytic behavior and synergistic effect of nanostructured mesoporous CuO-MnOx-CeO2 catalysts for chlorobenzene destruction

Shen

et al. 2014

Applied Surface Science

101

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“…Although Zhu et al [46] associated the absence of CuO XRD reflections to the high dispersion of such species in the cases of low copper content, the existence of trace copper and cerium solid solution formation was not discarded at all because of the broadening of the CeO 2 reflections. Similarly, Mariño et al [47,48] studied a series of CuO x /CeO 2 catalysts prepared by the urea thermal decomposition method with copper contents up to 60 at.% and they also indicated that the solid solution could be present even if it were hardly detectable by XRD.…”

Section: Physico-chemical Characterizationmentioning

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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“…Este processo se repete continuamente. 8,[30][31][32] Além disso, Manzoli et al observaram que a boa atividade destes catalisadores está relacionada com as espécies de cobre superficiais e induzidas pela interação destas com a céria (forte interação metalsuporte), fator determinante para a boa atividade destes sólidos. 32 Os sólidos suportados em céria/titânia tiveram atividade catalítica satisfatória, no entanto, inferiores aos sólidos suportados em céria.…”

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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Preferential oxidation properties of CO in excess hydrogen over CuO-CeO2 catalyst prepared by hydrothermal method

Cited by 93 publications

References 44 publications

Catalytic behavior and synergistic effect of nanostructured mesoporous CuO-MnOx-CeO2 catalysts for chlorobenzene destruction

Catalytic behavior and synergistic effect of nanostructured mesoporous CuO-MnOx-CeO2 catalysts for chlorobenzene destruction

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

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

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