CO adsorption on the "29" Cu_xO/Cu(111) surface: An integrated DFT, STM, and TPD study

The elucidation of an accurate atomistic model of surface structures is crucial for the design and understanding of effective catalysts, a process requiring a close collaboration between experimental observations and theoretical models. Any developed surface theoretical model must agree with experimental results for the surface when both clean and adsorbate covered. Here, we present a detailed study of the adsorption of CO on the "29" Cu_xO/Cu(111) surface, which is important in the understanding of ubiquitous Cu-based catalysis. This study uses scanning tunneling microscopy, temperature-programmed desorption, and density functional theory to analyze CO adsorption on the "29" Cu_xO/Cu(111) surface. From the experimental scanning tunneling microscopy images, CO was found to form six different ordered structures on the "29" Cu_xO/Cu(111) surface depending on the surface CO coverage. By modeling the adsorption of CO on our atomistic model of the "29" Cu_xO/Cu(111) surface at different coverages, we were able to match the experimentally observed CO ordered structures to specific combinations of sites on the "29" Cu_xO/Cu(111) surface. The high degree of agreement seen here between experiment and theory for the adsorption of CO on the "29" Cu_xO/Cu(111) surface at various CO coverages provides further support that our atomistic model of the "29" Cu_xO/Cu(111) surface is experimentally accurate.