High Performance p-Si/Ni3S2 Photocathode for Photoelectrochemical Hydrogen Evolution in Neutral Solution

In the renewable energy field, solar-driven photoelectrochemical (PEC) water splitting into H 2 which has features of high energy density, high conversion efficiency and non-pollution is an efficient, inexpensive way to relieve the energy crisis. Silicon, with a bandgap of 1.1eV as an earth-abundant and efficient solar light absorption material is considered to be one of the most promising candidates for hydrogen generation in PEC devices. However, at present, most of the hydrogen evolution reactions are studied in heavily acidic condition such as 0.5M H 2 SO 4 , as for practical application, acid condition is high-cost and not environment-friendly. It’s necessary and challenging to explore photocathodes which can be used in neutral solution. The low-cost and stable transition metal sulfides materials as electrocatalysts for water splitting have grabbed more attention of researchers in recent years. Their suitable bandgap can make them absorb light over a wide range so that the solar energy can be fully used. In this study，it was found that Ni 3 S 2 was an excellent electrocatalyst for hydrogen evolution in neutral solution. Moreover, p-Si /Ni 3 S 2 core/shell array shows an enhanced PEC performance due to the cooperation of p-Si array’s excellent light harvesting and the optical properties of flake-like Ni 3 S 2 . By tuning the material’s composition, morphology and structure, their optical properties and stability can be optimized and applied in neutral solution. This work will generate significant new knowledge of the stable and unique core-shell nanostructure and make a meaningful contribution to the industrial application of potential hydrogen energy.