a Osaka National Research Institute, AIST, Midorigaoka 1-8-31, Ikeda Osaka 563-8577 Japan
b Department of Applied Chemistry, Osaka Institute of Technology, Omiya 5, Asahi-ku Osaka 535-1855 Japan
Abstract:
Supporting Pt and Pd catalysts have been examined for the reduction of NO with H2 in the presence of oxygen and moisture. All catalysts showed a conversion maximum in the NO reduction at around 373 K. An additional conversion maximum was found to appear at around 573 K over several metal oxides supporting Pd, and Pd/TiO2 gave the highest conversion at around 573 K among the catalysts tested. In the reaction at 373 K, NO might be reduced directly by H2 both on Pt and Pd catalysts to give N2 and N2O. At the conversion maximum of the Pd/TiO2 catalyst at 575 K, however, in situ generated NO2 seems to react with H2.