(684e) Developing a Theoretical Model to Unravel the Importance of Adsorbate Effects in Chemisorption on Surface Alloys
AIChE Annual Meeting
Friday, November 18, 2022 - 9:12am to 9:30am
Understanding chemisorption behavior is essential for designing material surfaces with optimal characteristics. The chemical bonding between adsorbates and surfaces (chemisorption) has a significant influence on nearly every discipline of surface science, including applications in catalysis, corrosion, and nanotechnology. To enhance our fundamental understanding and to guide in rational material design, the development of electronic-structure-based methods to accurately predict chemisorption behavior is of great importance. Existing approaches for describing chemisorption â including the Newns-Anderson model, d-band model, models based on coordination numbers, and data science approaches â have made significant contributions. However, these approaches are inadequate for capturing broad trends in the periodic table, particularly for multicomponent alloys. One common factor limiting these models is the overlook of adsorbate-induced effects on the surface electronic states. To overcome this, we introduce a new theory-derived model for predicting chemisorption energies on surfaces of transition metal alloy. We integrate adsorbate-induced perturbations to the adsorption site with properties of the electronic d-band of the substrate. These perturbations interact with the chemical environment of the site where local variations yield different responses in the chemisorption behavior. These variations explicitly give rise to deviations from the typical linear behavior of the adsorption energy with electronic structure descriptors such as the d-band center. We find a mean absolute error of 0.13 eV on comparing the adsorption energies of various adsorbates (O, N, CH, and Li) on a wide variety of transition metal surface alloys to density functional theory-estimated values, highlighting the robustness of our approach. The model is fully transparent and is based on a siteâs first and second d-band moments and the d-band filling of alloying atoms in first coordination shell surrounding the site. This generalized theoretical model with additional physical insight and transparency provides the atomic-level guidance needed for designing complex alloys with desired catalytic properties.