Unique NiCo₂S₄@ZnS/CdS Yolk–Shell Heterojunction for Efficient Visible-Light-Driven Photocatalytic Water Splitting

Abstract

Construction of rational heterojunction nanostructures is an effective approach to enhance photocatalytic performance of semiconductor photocatalysts for solar-driven hydrogen production from water splitting. Herein, a unique non-noble-metal hollow heterostructure NiCo 2 S 4 @ZnS/ CdS assembled by a ZnS/CdS light absorber with tunable compositions and a yolk−shell NiCo 2 S 4 cocatalyst was constructed for the first time. Interestingly, the yolk−shell NiCo 2 S 4 microspheres have a uniform size, and the composition of the ZnS/CdS coating layer can be tuned via adjusting the cation-exchange reaction time. Remarkably, such hollow NiCo 2 S 4 @ZnS/CdS yolk−shell heterostructures displayed enhanced H 2 evolution reaction (HER) activity of 20.17 mmol•g −1 •h −1 under visiblelight (λ > 420 nm) irradiation, approximately 14.4-and 5.6-fold that of ZnS/ CdS and 3 wt % Pt-loaded ZnS/CdS, respectively. Moreover, the NiCo 2 S 4 @ ZnS/CdS hybrids owned favorable photocatalytic stability as confirmed by the cycling and long-term H 2 evolution tests. The excellent photocatalytic capacity of NiCo 2 S 4 @ZnS/CdS can be ascribed to the heightened light absorption enabled by the yolk− shell architecture, efficient charge transfer and separation by the interfacial heterojunctions, as well as numerous active sites from the NiCo 2 S 4 cocatalyst. The findings presented here could enlighten the rational structural regulation of semiconductor nanomaterials to promote solar conversion and utilization.

Performance evaluation of Zr(CUR)/NiCo2S4/CuCo2S4 and Zr(CUR)/CuCo2S4/Ag2S composites for photocatalytic degradation of the methyl parathion pesticide using a spiral-shaped photocatalytic reactor

“…In recent years, different types of binary and ternary composites containing NiCo 2 S 4 were proposed for photocatalytic degradation purposes. NiCo 2 S 4 /ZnIn 2 S 4 , 14 NiCo 2 S 4 / ZnS/CdS, 15 and ZnO/NiCo 2 S 4 QDs-OVs 16 are examples of constructed materials to degrade organic pollutants. Furthermore, Ag 2 S as a n-type semiconductor with unique structure and excellent optical properties was chosen for coupling to NiCo 2 S 4 and CuCo 2 S 4 to preparing high-performance photocatalysts.…”