Kinetic study and the effect of particle size on low temperature CO oxidation over Pt/TiO2 catalysts

A series of Pt/TiO2 catalysts with various Pt particle sizes were prepared and tested for low temperature CO oxidation. The effect of Pt particle sizes on the reaction was investigated. It was found that turnover frequencies based on Pt dispersion varied as declined with increasing Pt particle size as a function of d(-0.86). However, turnover frequency based on Pt atoms located on the periphery of Pt-TiO2 interface remained constant at 40 degrees C, implying that these periphery Pt atoms were the active sites. Kinetic study was conducted to investigate reaction pathway on the catalyst. The derived power rate law expression was r=1.98 x 10(-7) (PCOPO20.19)-P-0.29 at 40 degrees C. Based on the kinetic results, elementary steps of this reaction were proposed, which involved chemisorption of CO on Pt atoms and chemisorption of O-2 on TiO2 and a reaction of these two species at the Pt-TiO2 interface. (c) 2013 Elsevier B.V. All rights reserved.