Au-Ag/CeO2 and Au-Cu/CeO2 Catalysts for Volatile Organic Compounds Oxidation and CO Preferential Oxidation

摘要

Oxidation of volatile organic compounds (VOC) and preferential oxidation of CO in the excess of H-2 (CO-PROX) were investigated over mono and bimetallic Au-Ag/CeO2 and Au-Cu/CeO2 catalysts. For the oxidation of VOC (2-propanol, ethanol and toluene) Au/CeO2 was the most active catalyst for the combustion of alcohols to CO2, Ag/CeO2 gave the best performance in the toluene total oxidation, Au-Ag/CeO2 and Au-Cu/CeO2 showed the highest selectivity to partial oxidation products. For CO-PROX Au-Ag/CeO2 and Au-Cu/CeO2 samples exhibited higher CO2 yield at low temperature than monometallic ones. The improved performance of bimetallic catalysts were accounted for an enhancement of surface ceria oxygens mobility caused by the addition of Ag or Cu to Au/CeO2 and involved in both investigated reactions. This effect was more evident on Au-Ag/CeO2 where a strong Au-Ag interaction occurred with formation of Au-Ag alloy or linked monometallic nanoparticles.