Ultrafast Deposition of NiFe Metal-organic Framework Catalysts Boosts BiVO4 Photoanode for Efficient Solar Water Splitting

Abstract

The severe photocorrosion of BiVO₄ limits its application in solar energy conversion in the long-term photoelectrochemical stability test. Herein, we synthesized a Fe@Ni-MOFs/BiVO₄ photoanode by a simple ultrasonic method and ultrafast deposition, which avoids the problems of damaging the surface structure of photoelectrode. The Fe@Ni-MOFs/BiVO₄ shows a photocurrent density of 4.89 mA cm^-2 at 1.23 V_RHE with an onset potential of 0.25 V_RHE under one sun illumination. Importantly, a stability over 30 h at 0.7 V_RHE can be obtained, which is so far the best stability character for MOFs-based cocatalysts decorated on BiVO₄ . During operation, Fe@Ni-MOFs transforms into a homogeneous and active hydroxide layer covering the surface, which exposes more active sites for OER reactions. This work demonstrates a simple strategy for MOFs co-catalysts to obtain fast hole transfer capability and reduce carrier recombination, thereby improving PEC performance.

Keywords: BiVO4 photoanode; Fe@Ni-MOFs; oxygen evolution; photostability; reconstruction structure.