Hydroxylation of Rutile TiO$_2$ (110) Surface Enhancing Its Reducing Power for Photocatalysis

TL;DR

This study uses density functional theory to show that hydroxylation of rutile TiO$_2$ (110) surfaces raises band edges, thereby improving its reducing power for photocatalytic applications.

Contribution

It reveals the physical mechanism by which surface hydroxyl groups induce band edge shifts, enhancing photocatalytic reducing power of TiO$_2$ (110).

Findings

Hydroxylation elevates TiO$_2$ band edges.

Surface hydroxyls create electric dipoles affecting electronic structure.

Enhanced reducing power for photocatalysis due to hydroxyl-induced band shifts.

Abstract

Hydroxylation of the rutile TiO$_2$ (110) surface has attracted much attention as the excess unpaired electrons introduced by hydroxyls play a critical role in surface chemistry and photocatalysis process of this material. In this work, based on density functional theory calculations with the Hubbard U correction, the electronic structures of the hydroxylated TiO$_2$ (110) surfaces have been studied. One interesting effect is found that the hydroxylation can elevate band edges of TiO$_2$, and thus can enhance its reducing power for photocatalysis. The underlying physical mechanism for such shifts of the band edges are associated with the electric dipoles arising from the hydroxyl groups on the surface.