Investigation of performances of commercial diesel oxidation catalysts for CO, CH, and NO oxidation.

Four commercial monolithic diesel oxidation catalysts (DOCs) with two different platinum group metal (PGM) loadings and Pt:Pd ratios of 1:0, 2:1, 3:1 (w/w) were investigated systematically for CO, CH, and NO oxidation, CO-CH co-oxidation, and CO-CH-NO oxidation reactions via transient activity measurements in a simulated diesel engine exhaust environment. As PGM loading increased, light-off curves shifted to lower temperatures for individual and co-oxidation reactions of CO and CH. CO and CH were observed to inhibit theoxidation of themselves and each other.