Showing papers by "Changbin Zhang published in 2007"

Catalytic decomposition of N2O over CeO2 promoted CO3O4 spinel catalyst

Abstract: A series of CeO2 promoted cobalt spinel catalysts were prepared by the co-precipitation method and tested for the decomposition of nitrous oxide (N2O). Addition of CeO2 to Co3O4 led to an improvement in the catalytic activity for N2O decomposition. The catalyst was most active when the molar ratio of Ce/Co was around 0.05. Complete N2O conversion could be attained over the CoCeO.05 catalyst below 400 degrees C even in the presence of O-2, H2O or NO. Methods of XRD, FE-SEM, BET, XPS, H-2-TPR and O-2-TPD were used to characterize these catalysts. The analytical results indicated that the addition of CeO2 could increase the surface area Of Co3O4, and then improve the reduction of Co3+ to Co2+ by facilitating the desorption of adsorbed oxygen species, which is the rate-determining step of the N2O decomposition over cobalt spinel catalyst. We conclude that these effects, caused by the addition of CeO2, are responsible for the enhancement of catalytic activity Of Co3O4. (c) 2007 Elsevier B.V. All rights reserved.

Self-assembly of novel mesoporous manganese oxide nanostructures and their application in oxidative decomposition of formaldehyde

Abstract: Monodisperse manganese oxide honeycomb and hollow nanospheres have been prepared facilely at room temperature by varying the molar ratio of KMnO4 and oleic acid. These new nanomaterials were characterized by XRD, SEM, EDS, TEM, and BET measurements. They had robust nanostructures and were stable even after ultrasonic treatment (40 kHz, 120 W) for 30 min. A plausible mechanism of the formation of manganese oxide nanostructures was proposed. The manganese oxide nanomaterials showed high catalytic activities for oxidative decomposition of formaldehyde at low temperatures. Complete conversion of formaldehyde to CO2 and H2O could be achieved, and harmful byproducts were not detected in effluent gases. The catalytic activity of manganese oxide hollow nanospheres was much higher than that of honeycomb nanospheres, although the surface area of the latter was nearly 2 times as high as that of the former. The mechanism of such morphology-dependent catalytic activity was discussed in detail. The catalytic activities...

Catalytic decomposition of N 2 O over CeO 2 promoted Co 3 O 4 spinel catalyst

Abstract: A series of CeO2 promoted cobalt spinel catalysts were prepared by the co-precipitation method and tested for the decomposition of nitrous oxide (N2O). Addition of CeO2 to Co3O4 led to an improvement in the catalytic activity for N2O decomposition. The catalyst was most active when the molar ratio of Ce/Co was around 0.05. Complete N2O conversion could be attained over the CoCe0.05 catalyst below 400 8C even in the presence of O2 ,H 2O or NO. Methods of XRD, FE-SEM, BET, XPS, H2-TPR and O2-TPD were used to characterize these catalysts. The analytical results indicated that the addition of CeO2 could increase the surface area of Co3O4, and then improve the reduction of Co 3+ to Co 2+ by facilitating the desorption of adsorbed oxygen species, which is the rate-determining step of the N2O decomposition over cobalt spinel catalyst. We conclude that these effects, caused by the addition of CeO2, are responsible for the enhancement of catalytic activity of Co3O4. # 2007 Elsevier B.V. All rights reserved.