Reinforced photogenerated electrons transfer on a novel graphdiyne (CnH2n-2) based heterojunction for enhanced photocatalytic hydrogen production

The development of non-noble metal catalysts with adjustable electronic structures is one of the strategies for the sustainable development of photocatalytic technology. Herein, graphdiyne (GDY) was prepared by mechanical ball milling and coupled with semi-metallic CoS2 to form a typical S-scheme heterojunction photocatalyst. The introduction of curly thin layer GDY avoids the agglomeration of CoS2 particles and provides a substrate for the dispersion of CoS2 nanoparticles, forming a tighter contact interface and shorter carrier migration distance. Based on the electronic structure advantages of GDY, that is, bond-order average effect and dispersed electron delocalization structure, a large-scale electron transfer space is formed, which makes it a charge acceptor with rich surface active centers. The formation of heterojunction between CoS2 and GDY can effectively improve the light energy efficiency and accelerate the carrier transfer, thus showing good hydrogen evolution activity and stability. In addition, the S-scheme carrier transfer mechanism, that is, the spatial separation of photogenerated carriers with strong redox ability, is demonstrated by in-situ irradiation X-ray photoelectron spectroscopy and density functional theory (DFT) calculation. This work expands the application of GDY prepared by mechanical ball milling in heterojunction photocatalysts.

Automated summary

This study prepared graphdiyne (GDY) by mechanical ball milling and coupled it with CoS2 nanoparticles to form a heterojunction photocatalyst. The introduction of GDY improved the carrier migration and energy efficiency, resulting in enhanced hydrogen evolution activity.