An Efficient, Visible-Light-Driven, Hydrogen Evolution Catalyst NiS/Znx Cd1-x S Nanocrystal Derived from a Metal-Organic Framework

Abstract

Photocatalytic water splitting for hydrogen production using sustainable sunlight is a promising alternative to industrial hydrogen production. However, the scarcity of highly active, recyclable, inexpensive photocatalysts impedes the development of photocatalytic hydrogen evolution reaction (HER) schemes. Herein, a metal-organic framework (MOF)-template strategy was developed to prepare non-noble metal co-catalyst/solid solution heterojunction NiS/Zn_x Cd_1-x S with superior photocatalytic HER activity. By adjusting the doping metal concentration in MOFs, the chemical compositions and band gaps of the heterojunctions can be fine-tuned, and the light absorption capacity and photocatalytic activity were further optimized. NiS/Zn_0.5 Cd_0.5 S exhibits an optimal HER rate of 16.78 mmol g^-1 h^-1 and high stability and recyclability under visible-light irradiation (λ>420 nm). Detailed characterizations and in-depth DFT calculations reveal the relationship between the heterojunction and photocatalytic activity and confirm the importance of NiS in accelerating the water dissociation kinetics, which is a crucial factor for photocatalytic HER.

Keywords: NiS/ZnxCd1−xS heterojunctions; hydrogen evolution; metal-organic frameworks; photocatalysis; water splitting.