Graphdiyne surface-modified CuS-GDY/LaCoO3 S-scheme heterojunctions for enhanced photocatalytic hydrogen evolution

Abstract

An effective strategy to enhance the photocatalytic hydrogen evolution activity is to rationally guide the photogenerated carrier migration. In this work, a novel carbon-based material CuS/Graphdiyne (CuS-GDY), was synthesized via a Cu-surface mediated method. Subsequently, the peanut-shaped LaCoO₃ is distributed uniformly on the surface of the layered CuS-GDY via electrostatic self-assembly, forming stepped heterojunctions that accelerate the transfer of photogenerated carriers. The modified CuS-GDY facilitated further optimization of the electrical conductivity and electron transfer capabilities of GDY. Furthermore, the formation of a Schottky junction between CuS and LaCoO₃ facilitates electron egress from the conduction band of LaCoO₃, thereby enriching the catalyst with active sites. The combined effect of the S-scheme and Schottky junctions within the composite catalysts facilitates the separation and transfer of photogenerated carriers, as evidenced by in situ XPS, DFT theoretical calculations, and complementary characterization techniques. This study presents novel insights into the modification of GDY and a deeper comprehension of the heterojunction dynamics in catalyst systems.