Two-dimensional ZnO/BSe van der waals heterostructure used as a promising photocatalyst for water splitting: A DFT study

Abstract

Recently, two-dimensional (2D) materials have attracted considerable focus because of their charming properties. Using 2D heterostructure as a photocatalyst for water splitting is a popular strategy for hydrogen production, which is a clean resource. In this work, the first-principle calculations were implemented to investigate the structural, electronic, interfacial and optical properties of 2D heterostructure based on ZnO and BSe. The heterostructure is formed by van der Waals (vdW) interaction and has a type-II band structure, which can separate the photogenerated electron–holes constantly. At the same time, the band alignment demonstrates the heterostructure has a decent band edge positions for the oxidation and reduction reactions of water splitting at pH 0. Besides, the ZnO/BSe vdW heterostructure possesses high carrier mobility of about 2538.16 cm2 V−1·s−1 along armchair direction. The charge difference and potential drop across the interface of the ZnO/BSe vdW heterostructure were addressed, which can induce a large built-in electric field, and this built-in electric field also is an important role to prevent the recombination of the photogenerated charges. Moreover, the ability of optical absorption of the heterostructure can be improved by the external biaxial strain. This study provides a new possible method to design the efficient photocatalysts for water splitting.