Low Onset‐Potential Z‐Scheme Ta 3 N 5 ‐based Photoanode with Enhanced Light Harvesting and Charge Transport

Abstract Simultaneous enhancement of light harvesting and charge transport in photoelectrochemical (PEC) systems is a major challenge to achieving high solar‐to‐hydrogen efficiency. Here, a Ta 3 N 5 ‐Si Z‐scheme system is constructed to facilitate charge transport pathways from generation to catalysis, taking advantage of the exquisite bandgap and band position of Ta 3 N 5 . The tailored Ta 3 N 5 ‐Si junction with an NbN x electron mediator effectively establishes a Z‐scheme charge transport and enhances the driving force for water oxidation, reducing the onset potential by an increment in photovoltage. Moreover, the nitrogen‐doped CoFeO x co‐catalyst boosts hole dynamics and kinetics at the surface level, resulting in improved hole extraction for water oxidation catalysis. The synergy between the above strategies cooperatively expedites the charge separation and transport in a Ta 3 N 5 …