The adsorption characteristics and mechanism of C1 molecules on two-dimensional SrTiO3 films

Abstract

The microscopic mechanism of molecular adsorption is a key and yet to be fully resolved scientific issue. This study employs density functional theory combined with ab initio molecular dynamics simulations to systematically investigate the adsorption behavior of three representative C1 molecules (CO, CO₂, and CH₂O) on the surface of pristine and point-defective two-dimensional SrTiO₃ films, aiming to further understand the general principles of molecular adsorption. The findings indicate that the adsorption configurations of C1 molecules are primarily governed by electrostatic interactions, i.e., the high potential regions of the molecules tend to combine with the low potential regions of the surface, and vice versa. Besides, the adsorption strength is significantly affected by the distribution of valence electrons and the configuration of molecular orbitals. Moreover, charge transfer effects alter the distribution of electrostatic potential, thereby causing a transition in the configuration of adsorbed molecules. These discoveries are of significant importance for identifying reaction sites and predicting catalytic mechanisms.