The adsorption characteristics and mechanism of C1 molecules on two-dimensional SrTiO ₃ films

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 <i>ab initio</i> 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>i.e.</i>, the high potential regions of the molecules tend to combine with the low potential regions of the surface, and <i>vice versa</i>. 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.