Preparation of CuxCo1-x/Al2O3/Cordierite Monolithic Catalysts and the Catalytic Combustion of Toluene

A series of CuxCo1-x/Al2O3/cordierite (x = 0-1) catalysts were prepared using cordierite as a support, a boehmite primer sol as the first washcoat layer and copper as well as cobalt oxides as the activity washcoat layer. The structure of the catalysts was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and temperature-programmed reduction. Toluene was chosen as a model compound to evaluate the catalytic activity in a conventional fixed-bed quartz reactor. The results indicate that Cu-Co-O was present when the Cu content was low. CuO diffraction peaks were observed when the Cu content was high. Both Co2+ and Co3+ exist on the surface of the obtained monolithic catalysts while Cu2+ is the main Cu species. The addition of a certain amount of copper oxide improved the reducibility of the cobalt oxide, which enhanced the catalytic activity of the catalysts. All the obtained catalysts showed good activity for the catalytic combustion of toluene. The Cu0.5Co0.5/Al2O3/cordierite catalyst showed the best catalytic activity. Toluene was completely oxidized at 315 degrees C.