Simultaneous non-metal doping and cocatalyst decoration for efficient photoelectrochemical water splitting on hematite photoanodes

Hematite (α-Fe₂O₃) is one of the most promising photoelectrochemical (PEC) materials for efficient solar water splitting. However, the intrinsic drawbacks of poor electrical conductivity, short hole-diffusion length, and sluggish oxygen-evolution kinetics hinder the practical PEC applications on these hematite-based photoanodes. The hetero-elements doping and cocatalysts decoration are considered as effective strategies to address these concerns, and the exploration of simple and facile one-step process for both modifications is highly desirable. Herein, a new strategy is proposed for simultaneously realization of phosphorus (P) doping and cobalt phosphate (CoPi) decoration on hematite photoanode (CoPi/P-Fe₂O₃) in a one-step low temperature phosphidation process. The P-doping increases the conductivity and the CoPi decoration accelerates the water oxidation kinetics. The PEC performance of the CoPi/P-Fe₂O₃ photoanode has been determined with high photocurrent density of 0.89 mA cm⁻², corresponded to 82% enhancement as compared to the pristine hematite photoanode. The simple one-step process for combination of hetero-elements doping and cocatalysts decoration opens up new opportunities for enhancing PEC performance of hematite-based photoanodes.