Ni-doped ZnIn2S4 on stainless steel mesh as self-standing pH-all electrocatalyst for hydrogen evolution

The hydrogen evolution reaction (HER) is a cathodic reaction of water splitting which is crucial in energy conversion. However, its wide-scale industrial applicability is limited by the slow reaction kinetics and complex diffusion of generated gas bubbles. In this study, we chose the readily available, low-cost stainless steel as a conductive substrate and feasibly in-situ developed the active phase ZnIn2S4 and Ni-doped ZnIn2S4 on it as a high-rate cathode for HER in acidic, alkaline, and neutral conditions. The Ni-doped electrocatalysts, when compared to bare ZnIn2S4, have higher electrocatalytic activity for HER, with low overpotentials of only 259 mV and 224 mV, to generate a high current density of 100 mA cm−2 in 0.5 M H2SO4 and 1 M KOH, respectively, exhibiting obviously enhanced performance. The presence of Ni atoms is evident in EDS mapping, TEM analysis, and ICP technique. A detailed analysis of the electrochemical characteristics of the generated electrocatalysts was carried out to gain a better understanding of the effect of additional doping atoms. We not only demonstrate a feasible method for developing unique, stable and efficient HER electrocatalysts in all pH settings by comprehending the collaborative effect of the active phase, doped Ni atoms, and affordable stainless-steel substrate, but also point out new avenue to branch out self-standing HER electrocatalyst categories.