Microwave-assisted synthesis of ZnO/BiNbO4 heterojunctions for enhanced hydrogen production

Abstract

This work introduces a novel heterojunction between ZnO and BiNbO4, prepared through a microwave-assisted technique that significantly reduces time and energy consumption for the synthesis. The used method requires 48 minutes to obtain vertically aligned wurtzite ZnO films and 30 minutes to obtain globular orthorhombic/triclinic BiNbO4. The heterojunction exploits the suitable band alignment of ZnO and BiNbO4 to construct an S-scheme structure, achieving enhanced charge separation and transfer. The prepared ZnO/BiNbO4 heterojunction was used as a photoanode for water photosplitting, exhibiting a fourfold increase in photocurrents for oxygen evolution compared to pristine ZnO. The heterojunction has also demonstrated photocatalytic activity for hydrogen production that is 3.5 and 2 times higher than that of bare ZnO and BiNbO4, respectively. These findings highlight the promising potential of ZnO/BiNbO4 heterojunctions for advanced photocatalytic and photoelectrocatalytic applications, particularly in hydrogen production.