Electron‐rich Mn:NiFe‐LDHs onto BiVO ₄ photoanode for improved photoelectrochemical water splitting

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Rapid hole extraction from photoanodes to cocatalysts is a crucial prerequisite for the realization of highly efficient photoelectrochemical (PEC) water splitting. Herein, Mn‐doped nickel–iron layered double hydroxides (Mn:NiFe‐LDHs), as a co‐catalyst, were grafted on bismuth vanadate (BVO) for significantly improved charge transfer and stability simultaneously, in addition to the accelerated water oxidation kinetics. The detailed experimental and theoretical analysis collectively verify that Mn doping increases charge density around Ni and Fe sites. The electron‐rich Ni sites boost the kinetics of oxygen evolution reaction and promote the hole extraction simultaneously. Moreover, the electrons are transferred from electron‐rich Fe sites to V sites, which effectively restrains the dissolution of V 5+ ions and enhances the stability of BVO photoanodes. Consequently, the resulting Mn:NiFe‐LDH/BVO photoanode achieves a remarkable photocurrent density of 5.5 mA cm −2 at 1.23 V versus reversible hydrogen electrode (RHE) with excellent stability. The construction of electron‐rich oxygen evolution cocatalysts provides a promising strategy to promote the hole extraction and increase the stability for improved PEC performance.