Size effect of CoS2 cocatalyst on photocatalytic hydrogen evolution performance of g-C3N4

The main goal of researchers is to obtain cheap cocatalysts that can promote the photocatalytic activity of catalysts. In this work, a series of CoS2/g-C3N4 (denoted as CoS2/CN) composite photocatalysts were syn-thesized by photodepositing CoS2 on g-C3N4 surface. The size of CoS2 species could be tuned from single -atom to nanometer scale, which had effect on photocatalysis. The 5CoS2/CN sample with proper nano size of CoS2 cocatalyst had the best photocatalytic performance (1707.19 lmol g-1h-1) in producing H2 under visible light irradiation (k > 420 nm). Its photocatalytic activity was about 1434.6 times higher than that of pure g-C3N4 and almost equal with that of Pt/CN catalyst (1799.54 lmol g-1h-1). The Density Functional Theory (DFT) calculation results further suggested that the ability of accumulating the elec-trons of the cocatalyst was based on the size effect of CoS2, and the proper size of the cocatalyst efficiently promoted the separation of photogenerated electron-hole pairs.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

The researchers aim to find inexpensive cocatalysts that can enhance the photocatalytic activity of catalysts. In this study, a series of CoS2/g-C3N4 composite photocatalysts were synthesized by depositing CoS2 on the surface of g-C3N4. The size of CoS2 species was adjustable and affected the photocatalysis. The 5CoS2/CN sample with an appropriate nano size of CoS2 cocatalyst exhibited the best photocatalytic performance in producing H2 under visible light irradiation. Its photocatalytic activity was significantly higher than pure g-C3N4 and comparable to Pt/CN catalyst.