Strategic integration of nickel tellurium oxide and cobalt iron prussian blue analogue into bismuth vanadate for enhanced photoelectrochemical water oxidation

Bismuth vanadate (BVO) with a small band gap and suitable band edges is regarded as one of the promising photocatalysts for water oxidation. However, the short charge-transfer path limits its photocatalytic performance. Establishing a heterojunction and incorporating a co-catalyst are feasible methods to improve the photocatalytic ability of BVO by enhancing carrier transfer rates and reducing in-electrode resistances. In this study, nickel tellurium oxide (NTO) and cobalt iron Prussian blue analogues (CoFePBA) are incorporated into the BVO electrode to respectively develop a heterojunction and decorate co-catalyst for efficiently catalyzing the water oxidation reaction for the first time. Different amounts of CoFePBA are deposited on the NTO/BVO electrode by varying the electrodeposition durations to enhance exited charge generations and maintain high absorbance of incident light. The largest photocurrent density of 6.55 mA/cm² at 1.23 V versus reversible hydrogen electrode is attained for the optimal CoFePBA/NTO/BVO electrode prepared using an electrodeposition duration of 2 min. Excellent catalytic stability is also achieved, with the photocurrent retention of 91.9% after illuminating the electrode for 5000 s. This study provides blueprints for incorporating novel electrochemically active materials in the BVO system to realize heterojunction and co-catalyst strategies, thereby attaining excellent photocatalytic ability toward water oxidation.