Synergistic improvement of charge separation and injection on CuPc modified BiVO4 for efficient solar water oxidation

Bismuth vanadate has been investigated as a promising photoanode candidate for solar water splitting while the sluggish interface water oxidation reaction kinetics and severe charge recombination hinder its further development. In order to improve the reaction kinetics, oxygen evolution cocatalysts (OECs) have been widely adopted in PEC water oxidation, but the poor integration between the photoanode and OECs still remains unsatisfactory. In this study, copper phthalocyanine (CuPc) decorated BiVO4 photoanode was fabricated via a facile in situ solvothermal method. The optimized 3C2-CuPc/BiVO4 photoanode exhibits a photocurrent density of 3.24 mA/cm2 at 1.23 V vs. RHE, which is 3.23 times as high as that of bare BiVO4. This significant improvement can be attributed to the well -integrated structure between BiVO4 and CuPc with nitro functional groups, resulting in synergistically enhanced charge separation and injection efficiency. This work provides a promising demonstration for designing interfaces between molecular catalysts and photoanode absorbers for efficient photoelectrochemical (PEC) water oxidation.