Anchored Ni nanocrystals boosting BiVO4 photoanode for highly efficient water oxidation via in-situ generation of Ni@NiOOH co-catalyst

Ni nanocrystals are anchored on a bismuth vanadate (BiVO4) substrate by facile dip-coating and annealing procedures. The resulting Ni/BiVO4 hybrid photoanode achieves a remarkable PEC water splitting performances due to the in-situ generation of Ni (core)-NiOOH (shell) co-catalysts, contributing to the enhanced charge transfer, water oxidation dynamics and durability. [Display omitted] •Ni nanocrystals are anchored on BiVO4 through dip-coating and annealing procedures.•The Ni/BiVO4 photoanode achieves a remarkable performance for water splitting.•An ultrathin NiOOH layer is in-situ generated on Ni nanocrystal after activation.•The Ni@NiOOH couple the high electrical conductivity and oxygen evolution activity. In this work, Ni nanocrystals as oxygen evolution reaction co-catalysts for water splitting are anchored on a porous bismuth vanadate (BiVO4) photoanode through facile dip-coating and annealing procedures. The resulting Ni/BiVO4 hybrid photoanode achieves an outstanding photocurrent density of 4.41 mA/cm2 at 1.23 V vs RHE, 3.2 times higher than pristine BiVO4 photoanode. A favorable PEC durability can be observed for Ni/BiVO4 hybrid photoanode with only a 4.7 % decay of photocurrent density within 10 h. Furthermore, results of Raman spectrum, X-ray photoelectron spectroscopy (XPS) etc., confirm that an ultrathin amorphous NiOOH layer is in-situ generated on Ni nanocrystals after an activation process, forming a robust Ni@NiOOH co-catalysts. The unique core–shell structure enables the Ni@NiOOH co-catalyst to couple the high electrical conductivity and high oxygen evolution activity, contributing to the enhanced photoelectrochemical performance. Importantly, this study paves a facile strategy to accomplish the desirable co-catalyst/semiconductor coupling towards efficient solar fuels production.