Multi-interfacial engineering of a coil-like NiS–Ni2P/Ni hybrid to efficiently boost electrocatalytic hydrogen generation in alkaline and neutral electrolyte

Abstract

Developing highly efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) in alkaline and neutral media is crucial but still a significant challenge due to the sluggish multi-step reaction kinetics involved. The interface formed between two or more components in heterogeneous catalysts plays a critical role for electrocatalysis as it can tune the electron structure to enhance the catalytic performance. Herein, we report that multi-interface engineering of NiS, Ni₂P and Ni on Ni foam results in a unique coil-like NiS–Ni₂P/Ni hybrid electrocatalyst on Ni foam, which is synthesized through a two-step approach: firstly, electrodeposition of Ni microspheres on Ni foam (NF), followed by partial thermal sulfuration and phosphorization. Owing to the interfaces between NiS, Ni₂P and Ni, which function as electrochemical active sites and are beneficial for dissociative adsorption of water molecules, the resultant NiS–Ni₂P/Ni/NF exhibits much superior hydrogen evolution reaction (HER) catalytic activity with small overpotentials of 53 mV and 115 mV to deliver a current density of 10 mA cm⁻² in alkaline and neutral media. Remarkably, NiS–Ni₂P/Ni/NF needs a lower overpotential than Pt/C to achieve a higher current density of 100 mA cm⁻². Density functional theory calculations suggested that the real active sites are located at the multi-interface of NiS, Ni₂P and Ni, contributing an outstanding electrocatalytic performance. This work not only reports a highly efficient coil-like multi-interfacial NiS–Ni₂P/Ni hybrid electrocatalyst on Ni foam for hydrogen production, but also paves a new way for designing other highly efficient electrocatalysts.