Nickel–AntimonyElectrocatalyst for DurableAcidic Hydrogen Evolution Reaction in Proton Exchange Membrane Electrolyzers

Developing a nonprecious alternative to platinum as hydrogen evolution reaction (HER) catalyst in a proton exchange membrane water electrolyzer (PEM-WE) has been a long-standing pursuit in electrochemical water splitting. Here, we report the theory-aided discovery of a noble-metal-free NiSb electrocatalyst with high stability and activity for acidic HER, continuously operating over 3000 h at 2 A cm^–2 and 60 °C with a cell voltage of 2.28 V in the PEM-WE. This NiSb catalyst was identified through a comprehensive stability and activity evaluation framework with computations, incorporating rigorous aqueous stability assessment via Pourbaix diagram analysis. Further experimental studies confirmed the successful synthesis of NiSb and impressive performance for acidic HER, verifying the computational predictions. The record-high durability, high activity, and low cost make NiSb a promising alternative to Pt for practical application in PEM-WE.