Promising CoFe-NiOOH Ternary Polymetallic Cocatalyst for BiVO₄-Based Photoanodes in Photoelectrochemical Water Splitting

CoFe-NiOOH is developed for the first time as a ternary polymetallic surface oxygen evolution cocatalyst to enhance the photoelectrochemical (PEC) water splitting performance of BiVO4-based photoanodes. Excellent semiconductor/cocatalyst interface matching reduces the recombination ratio of photogenerated carriers. Because of the lower overpotential and faster hole injection rate, BiVO4/CoFe-NiOOH photoanodes exhibit excellent PEC performance: photocurrent of 1.54 mA/cm2 [at 1.23 V vs reversible hydrogen electrode (RHE)], incident photon-to-current conversion efficiency of 41.97% (at 420 nm), bias photon-to-current efficiency of 0.243% (at 0.3 V vs RHE), hole injection efficiency of 35.7% (at 1.23 V vs RHE), hydrogen evolution rate of 0.0157 μmol·cm–2·min–1, and oxygen evolution rate of 0.0089 μmol·cm–2·min–1. This work provides prospects for the development and utilization of ternary polymetallic cocatalysts for improving the PEC performance of semiconductor-based photoelectrodes.