Insights into Improving Photoelectrochemical Water‐Splitting Performance Using Hematite Anode

Designing an efficient photoanode is of great importance for photoassisted solar water splitting. Herein, a series of modifications to a nanorod structure hematite, to be used as anode for photoelectrochemical (PEC) water‐splitting reactions is designed. Ti doping, oxygen vacancy formation by N 2 treatment, TiO 2 passivation, and FeOOH cocatalyst decoration are explored for their roles and contributions to the improvement of the PEC water oxidation performance. It is found that Ti doping and N 2 treatment can greatly increase the charge carrier density, which has boosted the photocurrent. TiO 2 passivation enhances the photovoltage, resulting in a cathodic shift in the onset potential (≈170 mV with respect to prepassivation). Further, the FeOOH cocatalyst decoration improves the reaction kinetics, thereby improving the overall photoassisted water oxidation performance.