Prussian Blue Type Cocatalysts for Enhancing the Photocatalytic Water Oxidation Performance of BiVO₄

The efficiency of photocatalytic overall water splitting reactions is usually limited by the high energy barrier and complex multiple electron-transfer processes of the oxygen evolution reaction (OER). Although bismuth vanadate (BiVO₄ ) as the photocatalyst has been developed for enhancing the kinetics of the water oxidation reaction, it still suffers from challenges of fast recombination of photogenerated electron-hole pairs and poor photocatalytic activity. Herein, six M^II -Co^III Prussian blue analogues (PBAs) (M=Mn, Fe, Co, Ni, Cu and Zn) cocatalysts are synthesized and deposited on the surface of BiVO₄ for boosting the surface catalytic efficiency and enhancing photogenerated carries separation efficiency of BiVO₄ . Six M^II -Co^III PBAs@BiVO₄ photocatalysts all demonstrate increased photocatalytic water oxidation performance compared to that of BiVO₄ alone. Among them, the Co-Co PBA@BiVO₄ photocatalyst is employed as a representative research object and is thoroughly characterized by electrochemistry, electronic microscope as well as multiple spectroscopic analyses. Notably, BiVO₄ coupling with Co-Co PBA cocatalyst could capture more photons than that of pure BiVO₄ , facilitating the transfer of photogenerated charge carriers between BiVO₄ and Co-Co PBA as well as the surface catalytic efficiency of BiVO₄ . Overall, this work would promote the synthesis strategy development for exploring new types of composite photocatalysts for water oxidation.