Synergistic catalysis of carbon black oxidation by Pt with MoO3 or V2O5

A series of SiO2-supported MoO3, V2O5, and Pt catalysts were prepared for t he study of model soot oxidation with simulated diesel exhaust gas. Composi te samples of Pt with the metal oxides demonstrated higher oxidation activi ties than the single-component SiO2-supported MoO3, V2O5 or Pt catalysts in the absence of SO2 in the: reactant gas. Based on the effects of NO2 on ca rbon oxidation, a synergistic reaction mechanism was suggested to explain t he effects of combining Pt with the oxides: Pt catalyzes the oxidation of N O with gas phase O-2 to NO2, while MoO3 and V2O5 catalyze the oxidation of carbon with NO2. Finally, the effects of SO2 on the carbon oxidation reacti on were examined and discussed. (C) 2001 Elsevier Science B.V. All rights r eserved.