FeNiSn-based perovskite hydroxide modified Ti-Fe2O3 with interfacial regulation for photoelectrochemical water oxidation

Abstract

Coupling oxygen evolution catalyst (OEC) as a cocatalyst is a promising strategy to accelerate the oxygen evolution reaction (OER) kinetics. However, the charge transfer at the cocatalyst/semiconductor interface has been considered as the limiting factor. Meanwhile, the real action mechanism of the cocatalyst on the photoanode/electrolyte interface needs to be explored completely in building efficient photoanodes. Herein, FeNiSn(OH)6 modified Ti-doped α-Fe2O3 with good interface contact was synthesized by the co-precipitation and then post-annealing treatment. The results reveal a significant improvement in separation efficiency is guaranteed by the good interface contact between Ti-Fe2O3 and FeNiSn(OH)6 and the increased charge carrier density after the post-annealing treatment. Therefore, more photogenerated holes are captured by the surface states (SS). Additionally, the recombination behaviors of photogenerated charges at the surface are suppressed by regulating the SS after the deposition of FeNiSn(OH)6 and the post-annealing treatment. Consequently, FNS/Ti-Fe2O3-150 presents a significant 6.05-fold enhancement in photocurrent density compared to Ti-Fe2O3 (0.52 mA/cm2), accomplishing an impressive photocurrent density of 3.15 mA/cm2 at 1.23 V vs. RHE.