Improved Photoelectrochemical Performance of BiVO4 for Water Oxidation Enabled by the Integration of the Ni@NiO Core–Shell Structure

The development of highly efficient and stable photoelectrode materials is of significant importance for the conversion of solar energy into chemical fuels. Herein, a novel Ni@NiO/BiVO4 photoanode is designed and prepared for efficient water splitting by the deposition of Ni particles on the surface of BiVO4 with subsequent thermal treatment. The integration of the Ni@NiO core–shell structure can efficiently passivate the surface states and accelerate the oxygen evolution kinetics along with the in situ-generated NiOOH, consequently contributing to the significantly improved charge separation efficiency. The resulting Ni@NiO/BiVO4 photoelectrode enabled a photocurrent density of 2.6 mA/cm2 with a surface charge separation efficiency of nearly 80% at the potential of 1.23 VRHE—much better than the unmodified BiVO4 (1.8 mA/cm2, 64%).