Spectroscopic Study of a Cu/CeO2Catalyst Subjected to Redox Treatments in Carbon Monoxide and Oxygen

Martı́nez-Arias, A.; Fernández, M.; Soria, J.; Conesa, J.C.

doi:10.1006/jcat.1998.2361

Cited by 240 publications

(97 citation statements)

References 44 publications

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“…Thus, according to the literature reports, we could explain these experimental results in the following way: better Cu dispersion (in 10-CuZr) provides higher photoreduction of Cu 2+ , due to the X-ray irradiation during the XPS measurement [40]. The stabilization of Cu + ions on the surface of the catalyst is mainly due to the strong support interfacial interaction with these Cu species [41]. Therefore, the low energy XPS peak observed at 932.2 eV could be assigned to Cu + species which are interacted with ZrO 2 .…”

Section: Resultssupporting

confidence: 55%

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

et al. 2016

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Mesoporous CuO-ZrO 2 catalysts were prepared and calcined at 500˝C. The performance of the synthesized catalysts for benzylation of benzene using benzyl chloride was studied. The bare support (macroporous ZrO 2 ) offered 45% benzyl chloride conversion after reaction time of 10 h at 75˝C. Significant increase in benzyl chloride conversion (98%) was observed after CuO loading (10 wt. %) on porous ZrO 2 support. The conversion was decreased to 80% with increase of CuO loading to 20 wt. %. Different characterization techniques (XRD, Raman, diffuse reflectance UV-vis, N 2 -physisorption, H 2 -TPR, XPS and acidity measurements) were used to evaluate physico-chemical properties of CuO-ZrO 2 catalysts; the results showed that the surface and structural characteristics of the ZrO 2 phase as well as the interaction between CuO-ZrO 2 species depend strongly on the CuO content. The results also indicated that ZrO 2 support was comprised of monoclinic and tetragonal phases with macropores. An increase of the volume of monoclinic ZrO 2 phase was observed after impregnation of 10 wt. % of CuO; however, stabilization of tetragonal ZrO 2 phase was noticed after loading of 20 wt. % CuO. The presence of low-angle XRD peaks indicates that mesoscopic order is preserved in the calcined CuO-ZrO 2 catalysts. XRD reflections due to CuO phase were not observed in case of 10 wt. % CuO supported ZrO 2 sample; in contrast, the presence of crystalline CuO phase was observed in 20 wt. % CuO supported ZrO 2 sample. The mesoporous 10 wt. % CuO supported ZrO 2 catalyst showed stable catalytic activity for several reaction cycles. The observed high catalytic activity of this catalyst could be attributed to the presence of a higher number of dispersed interactive CuO (Cu 2+ -O-Zr 4+ ) species, easy reducibility, and greater degree of accessible surface Lewis acid sites.

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Section: Resultssupporting

confidence: 55%

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

et al. 2016

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“…The reduction temperature of peak α in CuO/CeO 2 -MnO x (CB) at 131 °C demonstrates a significant decrease compared with that in CuO/CeO 2 and CuO/CeO 2 -MnO x (DP). Generally, there are three kinds of copper species in CuO-CeO 2 and their reducibility follows this order [15][16][17][18] : highly dispersed Cu x O in contact with ceria particle ＞ isolated copper ions interacting with the support ＞ large clusters and bulk CuO phase that do not contribute to the activity. According to literatures 17,18 , large clusters and bulk CuO phase are reduced at temperature higher than 200 °C; isolated copper ions interacting with the support begin to be reduced at about 160 °C; highly dispersed Cu x O in contact with ceria is easy to be reduced at 127-160 °C.…”

Section: The Structural Studies Of Ceo 2 -Mno X Supportsmentioning

confidence: 99%

“…Generally, there are three kinds of copper species in CuO-CeO 2 and their reducibility follows this order [15][16][17][18] : highly dispersed Cu x O in contact with ceria particle ＞ isolated copper ions interacting with the support ＞ large clusters and bulk CuO phase that do not contribute to the activity. According to literatures 17,18 , large clusters and bulk CuO phase are reduced at temperature higher than 200 °C; isolated copper ions interacting with the support begin to be reduced at about 160 °C; highly dispersed Cu x O in contact with ceria is easy to be reduced at 127-160 °C. Thus, from the reduction characteristics of copper species associated to the H 2 consumption of peak α, it can be deduced that highly dispersed Cu x O interacted with supports and isolated copper ions are the main copper species for CuO/CeO 2 -MnO x , and the amounts of highly dispersed Cu x O in CuO/CeO 2 -MnO x (CB) are more than that in CuO/CeO 2 -MnO x (DP).…”

Section: The Structural Studies Of Ceo 2 -Mno X Supportsmentioning

confidence: 99%

EFFECT OF PREPARATION METHODS OF CeO2-MnOx MIXED OXIDES ON PREFERENTIAL OXIDATION OF CO IN H2-RICH GASES OVER CuO-BASED CATALYSTS

Gong

Wang

Zhang

2012

J. Chil. Chem. Soc.

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The CeO 2 -MnO x mixed oxides were prepared by deposition-precipitation (DP) and surfactant-templated (CB) methods, and then used as the support of CuO/ CeO 2 -MnO x catalysts. The samples were characterized by means of XRD, BET, H 2 -TPR, CO-TPD and XPS. Results show that preparation methods of CeO 2 -MnO x support have a direct effect on the physicochemical properties and catalytic activities of CuO/CeO 2 -MnO x catalysts for the CO preferential oxidation in H 2 -rich gases(CO PROX). CuO/CeO 2 -MnO x (CB) catalyst exhibits higher CO conversion and stability in H 2 -rich gases than CuO/CeO 2 -MnO x (DP), with 100% conversion of CO at 140 °C after a temperature cycle, which indicates that CeO 2 -MnO x (CB) as support of CuO based catalyst is more useful for CO PROX reaction than CeO 2 -MnO x (DP). Compared with CuO/CeO 2 -MnO x (DP), there are richer oxygen vacancies and more Mn 4+ species on the surface of CuO/CeO 2 -MnO x (CB), and stronger interaction between CeO 2 and MnO x in it. More amounts of active copper species and complicated transfer of electrons density on CuO/CeO 2 -MnO x (CB) also favour the activity of the catalyst.

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“…Los reactores utilizados generalmente constan de tres o cuatro niveles de catalizador (figura 1.6), cada nivel está formado por varios módulos de catalizador en forma de panal de abeja con dimensiones de 1x1x2 m [73] . • El sistema de gases sucios (High Dust): El reactor se dispone delante del precalentador de aire y funciona directamente con los humos de salida del quemador que llegan a alta temperatura y con una elevada concentración de partículas (figura 1.7).…”

Section: Catalizador Caracteristicasunclassified

“…Trabajos previos realizados con catalizadores CuO/CeO 2 reportaron una reducción del cobre en dos pasos, observándose un primer pico asociado a CuO finamente disperso, que interactuaba fuertemente con el cerio (130-175ºC) y un segundo pico entre 180-200ºC correspondiente a partículas más grandes de CuO que se encontraban débilmente asociadas con cerio [72][73][74] . Perfiles de reducción para el SnO 2 presentan un pico intenso centrado a 700ºC asociado a la reducción del SnO 2 a Sn 0 [19,20] .…”

Section: Termoreducción Programada (Trp-h 2 )unclassified

Reducción catalítica de Óxidos de Nitrógeno (NOx) en corrientes gaseosas

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Reducción catalítica de Óxidos de Nitrógeno en corrientes gaseosas Agradecimientos ________________________________________________________________ ______________________________________________________________________ AGRADECIMIENTOSA Dios todopoderoso, por estar conmigo en cada paso que doy, por fortalecer mi corazón e iluminar mi mente y por haber puesto en mi camino a aquellas personas que han sido mi soporte y compañía durante el desarrollo del presente trabajo.A mis tutores, Drs. Freddy E. Imbert y A. Eduardo Palomares G., por el apoyo que me brindaron en todas las etapas de investigación, análisis y elaboración del presente trabajo, permitiéndome generosamente utilizar el gran caudal de su conocimiento sobre la materia y su enorme experiencia, para poder desarrollar esta tesis.A los miembros del Jurado por su colaboración desinteresada y oportuna, aportando sugerencias valiosas en el desarrollo de este trabajo.

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Spectroscopic Study of a Cu/CeO2Catalyst Subjected to Redox Treatments in Carbon Monoxide and Oxygen

Cited by 240 publications

References 44 publications

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

Physico-Chemical and Catalytic Properties of Mesoporous CuO-ZrO2 Catalysts

EFFECT OF PREPARATION METHODS OF CeO2-MnOx MIXED OXIDES ON PREFERENTIAL OXIDATION OF CO IN H2-RICH GASES OVER CuO-BASED CATALYSTS

Reducción catalítica de Óxidos de Nitrógeno (NOx) en corrientes gaseosas

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