High solar-to-hydrogen efficiency in Arsenene/GaX (X = S, Se) van der Waals heterostructure for photocatalytic water splitting

Abstract

Using two-dimensional (2D) materials as photocatalyst for water splitting become a considerable technology for green and clean energy, where the candidate photocatalysts hold promising development of this field. Here, the monolayered Arsenene (As) and the group-III monochalcogenide, GaX (X = S, Se) are presented to construct the heterostructure, and the detailed theoretical study of the structural and electronic properties of the heterostructure are addressed by first-principle calculations. The As/GaX heterostructure are proved to be thermodynamic stable with intrinsic type-II band structure to prevent the recombination of the photogenerated electron–hole pairs and suitable band edge energy potential to induce the redox reaction for water splitting at pH value of 0. The calculated charge density demonstrates that the As layer is positively charged while the GaX layer is negatively charged. The obtained potential drop across the interface of the As/GaX heterostructure can result a built-in electric field, which also is a significant role to separate the photogenerated charges. Furthermore, the As/GaX heterostructure possess novel sunlight capturing performance and high solar-to-hydrogen efficiency, and all that promise the usage in photocatalytic water splitting for As/GaX heterostructure.