CO adsorption on Pt (1 1 1) and Pd (1 1 1) surfaces: A first-principles based lattice gas Monte-Carlo study

Interaction of carbon monoxide (CO) with transition metal surfaces is an essential part of CO oxidation catalysis. In this report, we investigate and compare CO adsorption behavior on Pt (1 1 1) and Pd (1 1 1) surfaces combining first-principles (FP) calculations and lattice gas Monte-Carlo (LG-MC) simulations. Our results indicate that despite stronger CO binding on Pd (1 1 1) at low coverage, more repulsive lateral interactions on Pd surface lead to a more rapid adsorption energy decrease with respect to coverage. This results in lower saturation coverage and weaker CO desorption energies on Pd (1 1 1), which could contribute to its excellent reactivity observed under high pressure reaction conditions.