Noble-metal-free hetero-structural CdS/Nb2O5/N-doped-graphene ternary photocatalytic system as visible-light-driven photocatalyst for hydrogen evolution

In this paper, visible-light-driven photocatalysts composed of CdS nanoparticles, Nb2O5 nanorods (NbR) and N-doped graphene (NGR) nanosheets for photocatalytic water reduction to produce hydrogen have been synthesized. Under visible light irradiation, the prepared ternary nanocomposites showed distinctly enhanced photocatalytic performance for hydrogen evolution compared to bare CdS, NbR and CdS/Nb2O5. The sample with 2 wt.% NGR exhibited the highest photocatalytic activity, which is ca. 7.7 times as high as that evolved from CdS. The enhancement of photocatalytic performance may be related to the unique one dimension (1D) Nb2O5 structure with high surface-to-volume ratio, which can provide intimate interfacial contact between NbR and CdS nanoparticles, as well as the CdS/Nb2O5 heterojunction structure and two dimension (2D) NGR, which enhance the separation efficiency of photogenerated charge carriers. This work provides a promising and cost-effective method by combining the 0D CdS nanoparticles, 1D Nb2O5 nanorods and 2D N-doped graphene to form a ternary photocatalytic system for highly efficient hydrogen evolution from water without using any noble metals.