EFFECT OF COPPER CONTENT ON PT-PD-CUO GAMMA-ALUMINA CATALYSTS FOR MOTORCYCLE SOOT CONVERSION/

Catalytic combustion of motorcycle soot particulates over gamma-alumin a-supported CuO, Pt, Pd, PtCuO, and Pd-CuO catalysts was studied. The catalyst coated with motorcycle soots was placed in a flow reactor to perform temperature-programmed oxidation. Results indicated that the C uO catalyst was quite effective for the catalytic combustion. The high activity of the CuO catalyst could be illustrated by a redox mechanis m and an induced particle-motion mechanism. A higher copper content en hanced the reducibility of the copper oxide and induced a higher activ ity for catalytic combustion until the copper oxide content reached 5 wt %. A redispersion phenomenon of the CuO species was observed and wa s consistent with the induced particle-motion mechanism. Additionally, the effect of the noble metal additive was to promote the activity of the CuO species by a mechanism including dissociative adsorption and spillover of oxygen.