The catalytic oxidation of carbon black, a model soot, over Ag/ZrO 2 was studied. Transmission electron microscopy observations revealed that Ag nanoparticles with sizes of 2-10 nm on the catalysts presented 3-10 wt% Ag loading. Temperature-programmed reaction and transient activity measurements of carbon black oxidation revealed that the oxidation rate also increased with an increasing number of Ag nanoparticles on the catalysts up to 5 wt% Ag loading. The catalytically active Ag species thus was concluded to be nanoparticles with sizes of 2-10 nm. ExperimentalAg/ZrO 2 catalysts containing 0.5-20 wt% Ag were prepared by means of an incipient wetness method using AgNO 3 (Wako Pure Chemical Industries) and ZrO 2 (RCS-H; Daiichi Kigenso)

No abstract

No abstract

No abstract

We investigated the total oxidation of toluene over Cu/MOx/SiO2 (M = metal) catalysts. Among the metal oxides used to modify the SiO2 support, TiO2 afforded the catalyst with the highest activity. The optimum Cu and TiO2 loadings were 3 and 10 wt %, respectively. Changes in the Cu loading had little influence on the activation energy of the toluene oxidation reaction. Cu/TiO2/SiO2 was more active than Cu/TiO2 because the Cu and TiO2 were more highly dispersed on the SiO2 support of the former. We characterized the Cu species by temperature-programmed reduction with NH3, which showed that in Cu/TiO2/SiO2, Cu2+ was reduced at a lower temperature and Cu+ at a higher temperature than in Cu/TiO2 or Cu/SiO2. That is, the TiO2-modified SiO2 was a good support for Cu because the modification widened the temperature range over which the Cu2+ <img align="middle" src="./Graphics/abst-86_20120210_1.jpg"/> Cu+ redox cycle occurred.