Bridging the Gap between CO Adsorption Studies on Gold Model Surfaces and Supported Nanoparticles

摘要

An in-depth understanding of CO adsorption on highly dispersed gold nanoparticles (AuNPs) is critically important to fully interpret the catalytic behavior of supported gold systems in processes such as CO oxidation, PROX (selective oxidation of CO in presence of a large excess of H2), or LT-WGS (low-temperature water gas-shift) reactions. Despite its relevance, the quantitative data and fundamental information presently available on the CO-Au interaction mainly comes from studies carried out on model single-crystal and thin-film surfaces under experimental conditions far from those at which catalytic assays on supported gold systems are typically run. Probably because of the very weak and singular nature of the CO-Au interaction, which on the basis of both theoretical and experimental studies is generally acknowledged to take place on low-coordination surface sites, and the additional contribution of the support, a few studies have been carried out that were aimed at estimating the amount of CO adsorbed at low temperature on powdered or model supported AuNPs. To our knowledge, however, none of these have arrived at a detailed quantitative description of this process under conditions close to those occurring in real catalytic reactions.