Scaling-Relation Kinetic Monte Carlo Simulations for CO Oxidation over Dilute Pt@Au Alloys

Catalytic low-temperature CO oxidation continues to be an important materials challenge. Technological catalysts are commonly based on Pd and Pt nanoparticles, which are CO poisoned at low temperatures, hindering O2 adsorption. Using first-principles-based kinetic Monte Carlo simulations, we explore dilute Pt@Au nanoalloys as a possibility to enhance the low-temperature activity by spatially separating CO and O2 adsorption. CO is on these systems absorbed on Pt sites, whereas O2 reacts molecularly from Au sites to form OCOO, which decomposes to CO2 and O. The dilute Pt@Au systems are found to have a higher activity than pure Au systems in a temperature range not accessible to Pt-only catalysts. The results show that dilute Pt@Au alloys in combination with Pt-only catalysts have the potential for CO oxidation in a wide temperature range.