Defective iron doped nickel sulfide as electrocatalyst for hydrogen evolution reaction

Exploring efficient and economic electrocatalyst to replace the expensive noble metal based materials toward the hydrogen evolution reaction has indispensable role for water splitting reaction. NiFe based materials have good hydrogen and oxygen evolution reaction efficiency but still were further explored to enhance their catalytic activity. In this work, we report, Fe doped NiS electrocatalyst for water electrolysis process. Additionally, the improvement of activity was done by creating sulphur vacancy following in situ NaBH₄ treatment in Fe doped NiS electrocatalyst, and named as Vs-Fe doped NiS. The catalyst exhibits magnificent HER performance with ultralow overpotential of 88 mV and 117 mV at a current density of 10 mA/cm² (J₁₀) and 20 mA/cm² (J₂₀), having a low Tafel slope value of 61 mV/dec in 1 M KOH solution. This material is highly stable for 12 h. Fe doping and vacancy creation in NiS results in an increase in charge movement, higher surface area and hence improved efficiency.