Surface oxygen vacancies of TiO2 nanorods by electron beam irradiation for efficient photoelectrochemical water splitting

Abstract

In this work, a high energy electron beam (EBI) with an energy of 0.1 MeV was applied to modify the surface structure of TiO₂ nanorod arrays (NRs). We have found that the photoelectrochemical (PEC) water splitting activity of the EBI-TiO₂ photoanode was enhanced greatly compared to that of pristine TiO₂ due to the enriched oxygen vacancies (V_O) introduced at the surface of TiO₂ NRs via EBI treatment. The concentration of surface V_O is easily controlled via the adjustment of irradiation doses, which is a key factor in influencing the PEC performance. After modification, the photocurrent density is markedly promoted without typical doping or catalyst modification, and is approximately double that of the pristine TiO₂. Systematic studies have been conducted to reveal the mechanism for the charge separation and transport induced by the EBI process.