Interplay between invasive single atom Pt and native oxygen vacancy in anatase TiO2(1 0 1) surface: A theoretical study

Abstract

The effects of invasive single atom Pt on native oxygen vacancy migration in anatase TiO2(1 0 1) surface, as well as their coupling effect on water dissociation are investigated by means of the first-principles calculations based on density functional theory (DFT). Our results show that introducing Pt atom as Pt-ads and Pt5c modes could accelerate the Ov migration effectively. However, the roles of Pt2c and Pt6c are to decelerate the Ov migration. Oxygen-poor condition is beneficial for forming Pt-ads/TiO2-x1(1 0 1) and Pt2c/TiO2-x2(1 0 1), whereas oxygen-rich condition is beneficial for forming Pt5c/Ti1-yO2-x1(1 0 1) and Pt6c/Ti1-yO2-x1(1 0 1). Under their optimal conditions, Pt5c and Pt6c substitutions could make oxygen Ov formation easier, while Pt-adsorption and Pt2c substitution show no effect on Ov formation. The effect of imported Pt atoms mainly applies to the paths where they are involved directly. When Pt substituted either Ti5c or Ti6c, Ov tends to distribute around it and decreases its coordination number to 4 for maintaining a planar coordinated configuration of Pt-O. The adjacent bimetal Pt4c-Ti4c site in Pt6c/TiO2-x(1 0 1) can serve as the active center for water dissociation reaction. These findings can provide a “quasi-dynamic” perspective to understand the catalytic process of single atom supported on metal oxide surfaces.