Electronic Optimization in V-Doped NiS Nanoarrays Enables High-Efficiency Sulfide Oxidation-Assisted Seawater Electrolysis
Jiaqiang Sun, Zongchen Wei, Zi‐Hui Zhang, Zhiwei Wang, Linfeng Xiao, Qian Liu, Guangzhi Hu, Xijun Liu
Abstract
The combination of hydrogen production and sulfide degradation represents a promising approach for energy-saving seawater splitting while generating valuable sulfur. Herein, we show that V-doping can regulate the electronic structure of NiS, thus optimizing the reactants/intermediates’ adsorption behaviors and reducing the corresponding energy barriers. Accordingly, for the sulfide oxidation reaction (SOR), the as-prepared catalyst needs a working potential of 0.62 V vs RHE to reach 100 mA cm –2 accompanied by high robustness over 70 h. Besides, it can also trigger the hydrogen evolution reaction (HER) activity with a low overpotential of 0.196 V vs RHE at 10 mA cm –2 . By coupling the SOR and HER in alkaline seawater, the electrolyzer can yield 100 mA cm –2 at 1.89 V, which is lower than that of conventional seawater splitting, significantly reducing the energy input. The formation of sulfur powder at the anode further confirms the economic feasibility of such a novel electrolysis system. This work shows an attractive attempt to construct outstanding NiS-based catalysts for sulfide degradation and simultaneous green hydrogen production.