Mechanistic study of two-dimensional CrS2/Sc2CF2 direct Z-scheme heterojunction as the solar-driven water-splitting photocatalyst

Abstract

Direct Z-scheme based on biomimetic artificial photosynthesis is a promising strategy to enhance photocatalytic activity. The search for direct Z-scheme photocatalysts is imperative, and the photocatalytic efficiency is mainly influenced by the separation rate of photogenerated electron–hole (e--h+) pairs and the light capture ability. Herein, a two-dimensional (2D) van der Waals (vdW) heterostructure consisting of a monolayer of CrS2 and Sc2CF2 is predicted based on density functional theory (DFT) as a promising direct Z-scheme photocatalyst for water splitting. The CrS2/Sc2CF2 heterojunction possesses a large energy band interleaving arrangement and a small interlayer band gap, and the orientation of the built-in electric field promotes interlayer carrier complexes, with electrons and holes localized at the highest redox energy level, respectively. In addition, the CrS2/Sc2CF2 heterojunction possesses a high overpotential driving force and excellent light harvest ability. Our calculations indicate that the CrS2/Sc2CF2 heterojunction is a promising new photocatalyst.