CoNiO₂ as a novel water oxidation cocatalyst to enhance PEC water splitting performance of BiVO₄

A strategy is proposed for modifying BiVO₄ photoanode with CoNiO₂ as a novel water oxidation cocatalyst to enhance PEC water splitting performance. The results show that CoNiO₂ has the following functions: reducing photogenerated charge recombination centers; providing trapping sites to promote charge separation; improving the stability of the overall system; providing more active sites; and offering a lower overpotential. The BiVO₄/CoNiO₂ photoanode has a higher photocurrent density (1.16 mA cm^-2 at 1.23 V vs. RHE), a lower onset potential (∼0.06 V vs. RHE), a larger IPCE (34.37%) and ABPE (0.163%), better stability and good rates of hydrogen evolution (0.0148 μmol cm^-2 min^-1) and oxygen evolution (0.0076 μmol cm^-2 min^-1). The strategy provides promising prospects for achieving efficient PEC water splitting performance using water oxidation cocatalysts.