Exfoliated carbon nitride nanosheets decorated with NiS as an efficient noble-metal-free visible-light-driven photocatalyst for hydrogen evolution

Abstract

A binary composite composed of two dimensional (2D) ultrathin carbon nitride (C₃N₄) nanosheets and NiS nanoparticles was synthesized and applied as a noble-metal-free photocatalyst for hydrogen evolution under visible light irradiation. The ultrathin nanosheets of C₃N₄ were obtained by a facile liquid exfoliation method and used as 2D supports for the deposition of NiS nanoparticles. In the binary composite, the ultrathin C₃N₄ nanosheets acted as a visible light responding semiconductor, and the NiS nanoparticles served as a noble-metal-free cocatalyst. The binary composite with an optimized composition gave a hydrogen evolution rate comparable to that of Pt modified C₃N₄. Moreover, compared to bulk C₃N₄, the exfoliated C₃N₄ nanosheets distinctly improve the photocatalytic performance for hydrogen evolution. The photocatalytic results combined with photoelectrochemical experiments show that C₃N₄ with an ultrathin structure promotes the electron–hole separation and transportation during the process of the photoinduced hydrogen evolution. This study displays a facile method to build a low-cost but effective photocatalyst for hydrogen production under visible light irradiation.