Effect of Co Doping on Electrocatalytic Performance of Co-NiS₂/CoS₂ Heterostructures

There are abundant water resources in nature, and hydrogen production from electrolyzed water can be one of the main ways to obtain green and sustainable energy. Traditional water electrolysis uses precious metals as catalysts, but it is difficult to apply in massive volumes due to low reserves and high prices. It is still a challenge to develop hydrogen electrocatalysts with excellent performance but low cost to further improve the efficiency of hydrogen production. This article reported a potential candidate, the Co-NiS₂/CoS₂ (material is based on NiS₂, and after Co doping, The NiS₂/CoS₂ heterostructure is formed) heterostructures, prepared by hydrothermal method with carbon paper as the substrate. In a 0.5 M sulfuric acid solution, the hydrogen evolution reaction with Co-NiS₂/CoS₂ as the electrode showed excellent catalytic performance. When the Co (Cobalt) doping concentration is increased to 27%, the overpotential is -133.3 mV, which is a drop of 81 mV compared with -214.3 mV when it is not doped. The heterostructure formed after doping also has good stability. After 800 CV cycles, the difference in overpotential is only 3 mV. The significant improvement of the catalytic performance can be attributed to the significant changes in the crystal structure and properties of the doped heterostructures, which provide an effective method for efficient electrocatalytic hydrogen production.