Charge Trapping at the Step Edges of TiO2 Anatase (101)

TL;DR

This study reveals that step edges on TiO2 anatase (101) surfaces trap excess electrons, influencing adsorption sites and defect interactions, with implications for titania's various applications.

Contribution

It combines experimental microscopy and theoretical calculations to demonstrate electron trapping at step edges and the role of defects in TiO2 anatase (101).

Findings

Electrons are trapped at step edges.

Steps serve as preferred O2 adsorption sites.

Defects like vacancies enhance electron localization.

Abstract

A combination of Photoemission, Atomic Force and Scanning Tunneling Microscopy/Spectroscopy measurements shows that excess electrons in TiO2 anatase (101) surface are trapped at step edges. Consequently, steps act as preferred adsorption sites for O2. In Density Functional Theory calculations electrons localize at clean step edges, this tendency is enhanced by O vacancies and hydroxylation. The results show the importance of defects for the wide-ranging applications of titania.