Propene and CO oxidation on Pt/Ce-Zr-SO42- diesel oxidation catalysts: Effect of sulfate on activity and stability

Platinum/cerium-zirconium-sulfate (Pt/Ce-Zr-SO42-) catalysts were prepared by wetness impregnation. Catalytic activities were evaluated from the combustion of propene and CO. Sulfate (SO42-) addition improved the catalytic activity significantly. When using Pt/Ce-Zr-SO42- with 10 wt% SO42-, the temperature for 90% conversion of propene and CO decreased by 75 degrees C compared with Pt/Ce-Zr. The conversion exceeded 95% at 240 degrees C even after 0.02% sulfur dioxide poisoning for 20 h. Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO42- support, and the increased number of Pt particles built up more Pt&+-(SO42-)(&-) couples, which resulted in excellent activity. The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO42- with good sulfur resistance. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.