Constructing an S-scheme heterojunction between defect modified MnCdS-VS/Se and H-GDY for enhanced photocatalytic hydrogen evolution

Abstract

Modifying electronic structures via vacancy engineering and elemental doping is a pivotal strategy for enhancing photocatalytic hydrogen evolution. This study investigates the creation of sulfur vacancies (V_s) in MnCdS and the incorporation of Se as a dopant. The filling of vacancy defects with Se atoms effectively enhances the photocurrent response and reduces charge transfer resistance. Subsequently, a composite catalyst featuring an S-scheme heterojunction was constructed with H-GDY, exhibiting superior photocatalytic hydrogen evolution activity. Furthermore, we corroborated the photocatalytic hydrogen evolution mechanism through Density Functional Theory (DFT), in situ X-ray photoelectron spectroscopy (in situ XPS) and Kelvin probe force microscopy (KPFM). This work provides an effective strategy for vacancy engineering and elemental doping in photocatalytic hydrogen evolution.