Carbon Monoxide Chemisorption on Palladium Surface

Abstract

This review summarizes literature findings on determination of Pd-particle size and specific surface area of supported Pd-catalysts. Chemisorption of CO is the most frequent method used for the purpose. The surface density of Pd atoms and chemisorbed CO molecules are the main parameters essential for the exact determination of the area. The generally accepted value – 0.84?10¹⁵ atoms cm^-2 – is the average value for Pd atoms in crystallographic planes (111), (100) and (101). The surface density of CO molecules is a crucial parameter for the reaction of CO with Pd, forming several bond types, which leads to different Pd/CO stoichiometries. The paper discusses various factors influencing the stoichiometry, such as the support type, use of promoters, Pd concentration and its particle size. The Pd-particle size cannot be reliably determined without using other techniques, such as TEM, FT-IR or temperature programmed desorption of CO.