“O-S” Charge Transfer Mechanism Guiding Design of a ZnIn₂S₄/SnSe₂/In₂Se₃ Heterostructure Photocatalyst for Efficient Hydrogen Production

Abstract

The purposeful regulation of the charge transfer pathway is of great significance for efficient H2 evolution activity. Herein, a ZnIn2S4 (DZIS)-based heterostructure of ZnIn2S4/SnSe2/In2Se3 (DZIS/SnSe2/In2Se3) was fabricated in which the "O-S" charge transfer was realized by constructing an Ohmic-like junction between DZIS and SnSe2, as well as a Schottky-like junction between SnSe2 and In2Se3. The Ohmic-like junction promoted the electrons in DZIS to transfer to SnSe2, whereas the Schottky-like junction accelerated the holes in In2Se3 to transfer to SnSe2. Benefiting from the peculiar "O-S" charge transfer, a large number of highly active photogenerated electrons were resolved in the conduction band of In2Se3, which contributed to the enhancement of H2 production activity. Under visible light irradiation, the optimized DZIS/SnSe2/In2Se3 exhibits a H2 evolution rate of 86.91 mmol·h–1·g–1 and an apparent quantum efficiency of 20.97% at 420 nm. This work reports an advanced prototype for realizing the desired charge transfer route through artificial heterointerface designing in an all-in-one photocatalyst.