Theoretical design of a Z-scheme photocatalyst for water splitting with excellent catalytic performance: ZnTe/ZrS2 heterojunction

Abstract

This study establishes a vertically stacked ZnTe/ZrS₂ heterojunction through first-principles calculations, systematically investigating its structural, electronic, and photocatalytic mechanisms. The results reveal that the ZnTe/ZrS₂ heterojunction exhibits a smaller bandgap than both ZnTe and ZrS₂ monolayers, featuring band alignment (type-II) enabled by the built-in electric field (BIEF) oriented from ZnTe towards ZrS₂. Under −4% to 4% twin-axis stress/tensile deformation, its energy level aligns with the photocatalytic water-splitting potentials at pH = 0. This heterojunction demonstrates an exceptional light absorption capability (2.234 × 10⁵ cm⁻¹) and achieves an energy conversion efficiency of 14.296%, confirming its efficient photon energy utilization. Additionally, the strain-induced enhancement of visible light absorption further expands its applicability. These findings collectively establish the ZnTe/ZrS₂ heterojunction as a highly prospective material for advanced photocatalytic water-splitting applications.