Photocharged Fe₂TiO₅/Fe₂O₃ Photoanode for Enhanced Photoelectrochemical Water Oxidation

Abstract

Photocharging is a novel and effective photoanode treatment for improving the photoelectrochemical water splitting performance. Here, a photocharged Fe2TiO5/Fe2O3 photoanode was prepared with a significantly increased photocurrent density. Furthermore, the photocharging effect could also be deactivated via a discharging treatment under dark conditions. By using X-ray absorption spectroscopy and electrochemical impedance spectroscopy, the photocharging effect was revealed to be attributed to the formation of Fe(IV) intermediates at the interface to accelerate the water oxidation kinetics. The results offer a detailed understanding on the mechanism of the photocharging effect in hematite, which may help in the design of highly efficient water splitting catalysts.