Rational design of a cobalt sulfide/bismuth sulfide S-scheme heterojunction for efficient photocatalytic hydrogen evolution

Abstract

Following a simple one-pot hydrothermal method, a Co9S8/Bi2S3 composite was successfully synthesized using peanut-like BiVO4 as a precursor. After hydrothermal sulfuration, BiVO4 was transformed into Bi2S3 while maintaining its original peanut-like structure. Meanwhile, Co9S8 nanoparticles were successfully coated onto the peanut-shaped surface of Bi2S3, forming an S-scheme heterojunction by in situ hydrothermal method. For the growth system of Co9S8, the special three-dimensional (3D) structure of Bi2S3 provides a good growth site for zero-dimensional (0D) Co9S8 nanoparticles, avoiding their aggregation and exposing, more reaction area of Co9S8. Moreover, the S-scheme heterojunction retains a more effective redox potential for this system and promotes the recombination of nonessential electron-hole pairs. The 0D/3D spatial structure and the construction of the S-scheme heterojunction provide a more efficient and convenient path for the transfer of photogenic charge, which greatly promotes the effective separation and diversion of the electrons. Besides, the cladding structure of the composite and the S-scheme heterojunction formed between Bi2S3 and Co9S8 complement each other for jointly improving the hydrogen production performance of Co9S8/Bi2S3.