Theoretical investigation of 2D/2D van der Waals SbPO4/BiOClxBr1−x heterojunctions for photocatalytic water splitting†

Abstract

Bismuth halogenoxide (BiOX)-based heterojunctions have garnered considerable attention recently due to their potential to enhance photocatalytic performance. However, the predominant focus on II-type heterojunctions has posed challenges in achieving the requisite band edge positions for efficient water splitting. In this investigation, stable van der Waals SbPO₄/BiOCl_xBr_1−x heterojunctions were constructed theoretically by using density-functional theory (DFT). Our findings demonstrate that SbPO₄ can modulate the formation of Z-scheme heterojunctions with BiOCl_xBr_1−x. The structural properties of BiOX were preserved, while reaching excellent photocatalytic capabilities with high redox capacities. Further investigation unveiled that the band edge positions of the heterojunctions fully satisfy the oxidation–reduction potential of water. Moreover, these heterojunctions exhibit notable absorption efficiency in the visible range, with absorption increasing as x decreases. Our research provides valuable theoretical insights for the experimental synthesis of high-performance BiOX-based photocatalysts for water splitting, leveraging the unique properties of SbPO₄. These insights contribute to the advancement of clean energy technology.