The decisive role of Au in CO diffusion on Pt surfaces: a DFT study

The modification of metallic surfaces with adsorbed atoms of a second metal is presented as an ideal method for producing electrocatalysts. In this work, we examined the role of Au atoms in the reactivity of Pt surfaces and their effect on the adsorption and diffusion of CO using first-principles calculations. Our comprehensive study utilized density functional theory (DFT) to analyze a variety of adsorption sites on single-crystal Pt structures, encompassing open and staggered configurations. The combined methodologies of the climbing image nudged elastic band (CI-NEB) and potential energy surfaces (PES) were employed to identify significant trends in the diffusional behavior of CO. These methods allowed for a thorough analysis of the movement and interaction of CO molecules, providing valuable insights into their diffusion properties. The findings of this study provide compelling evidence that the presence of Au inhibits the movement of CO towards highly reactive Pt sites. This contributes to a more thorough comprehension of polycrystalline metal surfaces with secondary metal deposits and their effectiveness in various electrocatalytic reactions.