Surface selective passivation and FexNi1-xOOH co-modified Fe2O3 photoanode toward high-performance water oxidation

Improving the water-splitting performance of hematite (a-Fe2O3) is still hindered due to its severe charge recombination and poor water oxidation kinetics. Herein, borate-treated Ti -Fe2O3 combined with a FexNi1-xOOH cocatalyst (FexNi1-xOOH/B/Ti-Fe2O3) greatly improved the performance of Ti-Fe2O3, and reached a notable photocurrent density of 3.39 mA/cm2 at 1.23 V vs. RHE. Transient surface photovoltage spectroscopy (TPV) directly reveals that [B(OH)4]- as a Lewis base can selectively passivate acceptor surface states on Ti -Fe2O3 photoanode surface, efficiently enhancing the charge separation efficiency. Moreover, the FexNi1-xOOH thin layer is devoted to further facilitate holes injection into the electrolyte, accelerating the water oxidation kinetics of Ti-Fe2O3 photoanode. The synergetic integration of acceptor surface states passivation and FexNi1-xOOH cocatalyst provides a novel strategy for the construction of efficient photoanodes by surface engineering. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.