Modulating the M–S motifs of a metallic electrocatalyst with low overpotential for the hydrogen evolution reaction in acidic electrolytes

Abstract

The development of non-precious metal catalysts with low overpotential and stability in acidic media is essential for reducing PEM electrolyzer costs, accelerating water splitting, inhibiting scale formation, and enabling large-scale green hydrogen production via seawater splitting. In this work, the in situ-formed S–Ni–M–S (M = Fe/Co) motif in R-FeNiCoS from electrochemical reconstruction optimized the catalyst's surface electronic structure, reducing the energy barrier for intermediate adsorption/desorption and significantly enhancing hydrogen evolution reaction (HER) activity, making it comparable to commercial platinum catalysts. Metal-like R-FeNiCoS is also close to a platinum plate in terms of its acidic HER performance, with overpotentials of 55 mV at 10 mA cm⁻² and 412 mV at 500 mA cm⁻² in 0.5 M H₂SO₄ electrolyte. Significantly, the reconstructed catalyst demonstrates superior long-term stability relative to the pristine material. This enhanced durability originates from electrochemical reconstruction that shortens Ni–S bonds, thereby optimizing local atomic coordination. More importantly, we report the first transition-metal catalyst for acidic seawater splitting that operates with both high stability and efficiency, providing a theoretical foundation for industrial seawater splitting.