La改性Pt-Pd/CeZrOx催化剂催化CO氧化性能及机理研究OA

CO catalytic oxidation technology is one of the key technologies for achieving"carbon neutrality"goal.La was introduced into CeZrOx and then noble metal Pt and Pd were loaded by impregnation method to prepare Pt-Pd based bimetallic catalysts.By characterization techniques such as XRD,XPS and H2-TPR,the effects of La modification on the structures,valence states of surface elements,adsorption properties and CO oxidation mechanism of the catalysts were explored.The results show that the La forms a stable CeZrLaOx solid solution structure with CeZrOx,increasing the specific surface area and concentration of surface oxygen vacancy of the catalysts.Pt-Pd/CeZrLaOx-5%exhibits excellent catalytic performance for CO oxidation.Under the temperature from 100℃to 450℃and space velocity of 150000 h-1,the reaction temperatures for CO conversion rates of 50%and 90%are 165.7℃and 222.0℃,respectively.In situ DRIFTS results indicate that on the Pt-Pd/CeZrOx,the linear adsorption of CO mainly takes place on Pd2+sites.La enhances the adsorption capacity of Pt2+sites to form a synergistic mechanism of Pt-Pd dual active sites,thereby promoting the rapid transformation of carbonate intermediates on the catalyst surface and improving the catalytic performances of the catalysts for CO oxidation.