First-principles study on the electronic properties and feasibility of photocatalytic water splitting on Z-scheme GaN/MoS2 heterostructure

Abstract

In recent years, van der Waals heterostructures have played a significant role in fields such as photocatalysis, quantum devices, sensors, etc., due to their excellent performance exhibited through synergistic interactions between multiple components and the highly customizable design. Two-dimensional transition metal dichalcogenides, with their highly tunable band structures and excellent electrochemical activity, are well-suited for constructing heterostructures. To investigate the specific electronic and photocatalysis properties of relative heterostructure, GaN/MoS2 heterostructure is constructed. Through the first-principles calculation, the Z-scheme GaN/MoS2 heterostructure shows a direct band gap of 0.869 eV. The excellent capability for separating the photogenerated carriers can be inferred from the conduction band offset as high as 1.915 eV and electrostatic potentials Ep of 6.361 eV. At pH = 14, oxygen evolution reaction can spontaneously occur under the photocatalytic action of the GaN/MoS2 heterostructure according to the negative Gibbs differences of −0.514 eV, −3.809 eV, −2.576 eV and −5.718 eV in the four-electron pathways. Therefore, the Z-scheme GaN/MoS2 heterostructure has great prospects in the application of optoelectronic devices and photocatalysis.