Rational design direct Z-scheme β-GeSe/HfS2 heterostructure by interfacial engineering: Efficient photocatalyst for overall water splitting in the wide solar spectrum

Abstract

The direct Z-scheme van der Waals (vdW) heterostructures that mimic the natural photosynthesis in plants raise a tremendous concern for photocatalysis applications. Herein, we propose a novel two-dimensional (2D) heterostructure comprised of HfS2 and β-GeSe monolayers. The most stable stacking configuration of the β-GeSe/HfS2 heterostructure is identified by using formation energy and molecular dynamic simulations. The direct Z-scheme photocatalytic property of the β-GeSe/HfS2 heterostructure was identified from band alignment, charge transfer, and built-in electric field. The β-GeSe/HfS2 heterostructure has a robust and excellent visible and ultraviolet optical absorption property (up to 105 cm−1). Moreover, the overall decomposition of water can proceed simultaneously and spontaneously on the surface of β-GeSe/HfS2 heterostructure when pH in the ranges from 7 to 12, without additional overpotential and co-catalyst. The highest solar-to-hydrogen (STH) efficiency of the heterostructure reaches 37.95%. This work not only provides a stepping stone into the design of high efficient Z-scheme photocatalyst but also demonstrates the enormous possibilities in two-dimensional heterostructures.