Cation-inhibitor and metal-support synergy for efficient and durable hydrogen evolution in natural seawater.

Li, Zhen; Wu, Lianqi; Li, Mengting; Lee, Lawrence Yoon Suk · Nat Commun · 2026

basic_science · Level V

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Abstract

Direct seawater electrolysis holds promise for sustainable green hydrogen production, yet its scalability is hindered by cathode fouling from Mg(OH)<sub>2</sub> and Ca(OH)<sub>2</sub> precipitates and high energy barriers for the hydrogen evolution reaction. Herein, we present a hybrid electrocatalyst, RuNiMo/MO/MN, integrating Ru single atoms with a NiMo, MoO<sub>2</sub>, and Mo<sub>2</sub>N heterostructure (NiMo/MoO<sub>2</sub>/Mo<sub>2</sub>N) to address these challenges through strong metal-support interactions and a cation-inhibitor strategy. Self-released NH<sub>4</sub><sup>+</sup> ions sequester local OH<sup>-</sup> to suppress precipitate formation, preserving active site accessibility, while Ru single atoms facilitate the injection of electrons to MoO<sub>2</sub>, optimizing H adsorption and reducing the energy barrier for H<sub>2</sub> evolution. RuNiMo/MO/MN cathode achieves a low overpotential of 259.2 mV at 10 mA cm<sup>-2</sup> and a high Faradaic efficiency of 99.5 %, with 2,000-h durability at 100 mA cm<sup>-2</sup> in natural seawater, surpassing commercial Pt/C. Furthermore, RuNiMo/MO/MN | |RuO<sub>2</sub> membrane electrode assembly sustains operation at 200 mA cm<sup>-2</sup> for over 250 h, with a hydrogen production cost of $1.36 per kg, below the US Department of Energy target of $2 per kg.