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.

Automated summary

This study synthesized six cocatalysts and deposited them on the surface of BiVO4 to improve the surface catalytic efficiency and photogenerated carries separation efficiency of BiVO4. The results showed that these catalysts can significantly enhance the photocatalytic water oxidation performance compared to pure BiVO4. Among them, the Co-Co PBA@BiVO4 catalyst was extensively characterized and found to capture more photons and improve the surface catalytic efficiency of BiVO4.