Engineering NiMo3S4|Ni3S2 interface for excellent hydrogen evolution reaction in alkaline medium

Abstract

Ideal electrocatalyst for hydrogen evolution reaction demands abundant reactive centers with high activity, fast electron and mass transfer, unhindered release of gas bubbles and long-term operation stability. Engineering different components' interface of the composite catalyst can lead to significantly enhanced performance. In this study, excellent activity of NiMo3S4|Ni3S2 seamlessly grown on 3D conductive framework has been demonstrated. Two-step approach has been adopted to synthesize the final catalyst via subsequently reacting (NH4)2MoS4 with Ni(OH)2 nanosheets array hydrothermally grown on nickel foam. As compared to the MoS2|Ni3S2 obtained by directly reacting (NH4)2MoS4 with the nickel foam, NiMo3S4|Ni3S2 demonstrates much superior behavior in terms of current density and Tafel value. On basis of the data analysis, the variance of electrochemical surface area (ECSA) and electron transfer resistance are not the key descriptor for performance of the electrocatalyst in this study. It is considered that the new formed interface between NiMo3S4|Ni3S2 contributes significantly to the boosted activity. Such nanostructured architecture shows promising results for hydrogen evolution reaction in alkaline medium with only 23.4 mV overpotential for the current density of 10 mA cm−2 and robust long-term stability during more than 20 h test.