利用地球上丰富的炭黑和NiS 2 双助催化剂修饰提高CdS纳米片体系的可见光产氢活性

Abstract CdS nanosheets (NSs) photocatalysts modified with dual earth-abundant co-catalysts of metallic carbon black (CB) and NiS 2 were synthesized by a two-step solvothermal/impregnation method. All the experiment results demonstrated that the co-loading of CB and NiS 2 could significantly enhance the photocatalytic H 2 -evolution activity of CdS NSs. The photocatalytic performance of the as-prepared CdS/CB/NiS 2 samples was tested under visible light ( λ ≥ 420 nm) by using an aqueous solution containing 0.25 mol L −1 Na 2 S-Na 2 SO 3 as the sacrifice agent. The CdS-0.5%CB-1.0%NiS 2 composite photocatalysts exhibited the highest H 2 -evolution rate of 166.7 μmol h −1 , which was approximately 5.16 and 1.87 times higher than those of pure CdS NSs and CdS-1.0%NiS 2 , respectively. The possible mechanism for the enhanced H 2 -evolution activity of CdS/CB/NiS 2 composite photocatalysts was proposed. The results showed that the enhanced photocatalytic H 2 -evolution activities could be ascribed to the co-loading of metallic CB and NiS 2 as co-catalysts onto the surface of CdS NSs. The excellent synergetic effect between the CB and NiS 2 could obviously improve visible light absorption, promote separation of photogenerated electron-hole pairs and boost the H 2 -evolution kinetics, thus leading to an enhanced activity for H 2 evolution. More interestingly, the metallic CB could not only act as a cocatalyst for H 2 evolution, but also serve as a conductive electron bridge to promote the charge migration. This work not only demonstrates that loading CB as a co-catalyst is a promising strategy to further boost the photocatalytic activity of CdS/NiS 2 composites, but also offers a new mechanistic insight into the construction of highly efficient and stable CdS NSs-based hybrid photocatalysts with dual earth-abundant co-catalysts for photocatalytic applications.