Synergistic performance of Zn2+ incorporated bimetallic Cobalt sulfide for the hydrogen evolution reaction in an alkaline medium

Cobalt sulfide (CoS) has gathered attention as a hydrogen evolution reaction (HER) catalyst. However, further research is required to enhance the catalytic performance CoS in terms of its durability, electrocatalytic activity and understanding its fundamental mechanism. Herein, we report a facile hydrothermal synthesis of Zn-substituted CoS with excellent electrocatalytic activity and stability towards the HER. Zn substitution in CoS has been carried out using different ratios of Zn. As a result, the synergistically doped ZnCoS-1 achieved an overpotential of 227 mV for the HER in order to achieve a current density of 10 mA cm−2 in 1 M KOH electrolyte. The performance enhancement observed with ZnCoS-1 is attributed to the Zn2+ dopant, which forms a bimetallic phase with CoS and acts as a strong Lewis acid that regulates the electronic characteristics for enhanced intermedial binding for catalytic activity. The prepared ZnCoS-1 catalyst exhibits excellent catalytic activity and robust stability towards the HER demonstrating the potential possibility to construct a water electrolyzer for sustainable hydrogen production. •ZnCoS nanoparticle were synthesized by a facile hydrothermal method.•Zn doped in CoS as ZnCoS-1 (0.25 Zn, 0.75 Co), ZnCoS-2 (0.5 Zn, 0.5 Co), ZnCoS-3 (0.75 Zn, 0.25 Co).•Prepared ZnCoS-1 delivered enhanced ESCA and Cdl compared to others.•Prepared ZnCoS-1 exhibited excellent catalytic activity towards HER.•ZnCoS-1 showcase enhanced stability in alkaline medium.