Considering the spin–orbit coupling effect on the photocatalytic performance of AlN/MX2 nanocomposites†
The enhanced photocatalytic mechanisms for the hybrid AlN/MX2 (MX2 = MoSe2, WS2, and WSe2) nanocomposites are systematically investigated by density-functional-theory calculations. Our theoretical calculations study the photocatalytic performance of AlN/MX2 nanocomposites with the inclusion of the spin–orbit coupling (SOC) effect. The results demonstrate that the band gaps of the AlN/MX2 bilayers vary from 1.72 to 1.93 eV, covering the main region of the visible light. All of the AlN–MX2 bilayers exhibit prominent visible and UV light response compared to their individual constituents, implying their potential applications as excellent light-absorbers. The AlN–MX2 heterobilayers are excellent photocatalysts for splitting water into hydrogen due to the perfect fit of band edge positions with respect to water reduction and oxidation potentials. Particularly, AlN–WS2 has type-II band alignment. Besides, the applied small biaxial tensile strain can not only effectively tune the band edge positions, but can also trigger an indirect–direct band gap transition in AlN–MX2 bilayers maintaining the excellent optical properties. Therefore, the strained AlN–MX2 bilayers are expected to be more promising candidates for photocatalysis. Overall, our theoretical predictions point toward the prospective future of novel AlN–MX2 heterostructures for photocatalysis.