Noble metal-free 0D–1D NiSx/CdS nanocomposites toward highly efficient photocatalytic contamination removal and hydrogen evolution under visible light

Abstract

The development of stable noble metal-free photocatalysts with efficient separation and transportation of the photogenerated electrons–holes is of crucial importance for promoting the application of photocatalysis technology. Herein, we propose an electron transfer strategy by reasonable design and fabrication of novel 0D NiS_x nanosheets as a co-catalyst on the surface of 1D CdS nanorods (CdS-NRs) to enhance photocatalytic hydrogen evaluation and contamination (Cr(VI), rhodamine B and bisphenol A) removal in water. Under visible light irradiation, the 0D–1D NiS_x/CdS-NR nanocomposite with 1.5% NiS_x loading gave a hydrogen evolution rate of 5.98 mmol h⁻¹ g⁻¹, which is about 5.3 times and 1.9 times higher than that of the native CdS-NRs and the optimal 1% Pt/CdS-NRs, respectively. Notably, good stability in the recycling test and a high apparent quantum efficiency of about 69.9% at 420 nm were also obtained. The 1.5% NiS_x/CdS-NRs exhibited enhanced photocatalytic contamination degradation efficiency of about 2 times higher than pure CdS-NRs. In this hybrid photocatalyst, 0D NiS_x nanosheets came into intimate interfacial contact with the surface of 1D CdS-NRs and played a similar role as noble metals, which could effectively improve the separation, transportation efficiencies and lifetime of photogenerated charge, and thus enhance the photocatalytic performance of CdS-NRs with more efficient conversion of solar energy. This work shows not only a possibility for the utilization of noble metal-free NiS_x as a co-catalyst in the photocatalysis, but also provides new insight into the design and fabrication of high-performance composite photocatalysts (such as NiS_x/g-C₃N₄ and NiS_x/Zn₃In₂S₆).