Effects of CO2 on the stability of Pd/CeO2-TiO2 catalyst for low-temperature CO oxidation

The stability of Pd/CeO2-TiO2 catalyst for low-temperature CO oxidation in the presence of CO2 was investigated. The effect of CO2 lied on reaction temperature and CO2 content. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) evidenced that the stimulative effect of CO2 should be ascribed to the CO2 dissociation, while the inhibited effect of CO2 was related to the carbonate accumulation and the mechanism alternation. The coexistence of H2O in the feed can inhibit the carbonate accumulation, which can be employed to explain the predominant role of H2O positive effect in the presence of CO2 and H2O together. (c) 2008 Elsevier B.V. All rights reserved.