2D SnO/MoO3 van der Waals heterojunction with tunable electronic behavior for multifunctional applications: DFT calculations

Abstract

Metal oxide van der Waals (vdW) heterostructures have attracted extensive attention in fundamental research and new-device design. The remarkable advantage of their tunable energy band structure makes it particularly important to develop versatile metal-oxide heterojunctions and to explore their mechanisms. Herein, 2D SnO/MoO3 vdW heterojunction is successfully constructed by first-principles calculations. Interestingly, the two layers are not limited by horizontal displacements when forming the heterojunction. The electronic structure of the SnO/MoO3 vdW heterojunction has been systematically investigated, and the underlying physical mechanism responsible for its band alignment has been further revealed. A Z-scheme charge transfer mechanism has been demonstrated in SnO/MoO3 with remarkable photocatalytic CO2 reduction capability. Most importantly, the band alignment can be efficiently tuned by varying the external electric field, indicating its multifunctional potential. Furthermore, the CO2 reduction reaction pathway and product selectivity occurring at the surface of 2D SnO/MoO3 vdW heterojunction can be optimized by adjusting the applied electric field. These findings will provide strong theoretical support for the design of novel multifunctional devices using SnO/MoO3 vdW heterojunctions.