Exploration of structure sensitivity of gold nanoparticles in low-temperature CO oxidation

Abstract

Gold nanoparticles (NPs) exhibit remarkable catalytic activity in low-temperature CO oxidation and their performance is highly dependent on size and shape. However, the underlying mechanism isn't fully understood yet. Herein, we combine density functional theory calculations, a multiscale structure reconstruction model, and kinetic Monte Carlo simulations to investigate the activity and structure sensitivity of Au NPs under different reaction conditions. The results indicate that increasing the partial pressure ratio of O₂ to CO leads to the decrease of optimal reaction temperature accompanied with the increase of performance. At low temperatures, the morphology of the NPs evolves to expose a higher proportion of (110) facets to promote the activity significantly. Moreover, the size dependence analysis suggests that O₂-rich conditions are favorable for small-sized NPs, while CO-rich conditions favor the large-sized NPs. These findings not only enrich our basic understanding of the structure–reactivity relationship and the origin of structure sensitivity in gold-catalysis, but provide a guide for rational design of Au catalysts.

Keywords: Kinetic Monte Carlo; CO oxidation; Gold catalysis; Nanoparticles.