CeO<sub>2</sub>-Stabilized Ni<sub>4</sub>Mo Alloys as Robust Alkaline Hydrogen-Evolving Electrocatalysts for Anion Exchange Membrane Water Electrolysis.

Mo, Yao Ren; Mao, Fang Xin; Chen, Ya Ni; Yang, Du Xiao; Liu, Ji Kai; He, Jing Jing; Yuan, Hai Yang; Niu, Qiang et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

The ampere-level alkaline hydrogen evolution reaction (HER) requires catalysts that combine high activity with long-term stability, yet benchmark NiMo alloys suffer from severe Mo leaching during operation. Here, we report a surface passivation strategy using CeO<sub>2</sub>-stabilized Ni<sub>4</sub>Mo alloys on MoO<sub>2</sub> (CeO<sub>2</sub>-Ni<sub>4</sub>Mo/MoO<sub>2</sub>) for robust alkaline HER. Experimental and theoretical results reveal that surface CeO<sub>2</sub> suppresses hydroxide-induced Mo dissolution while maintaining the reduced state of Ni<sub>4</sub>Mo and promoting interfacial water dissociation, thereby accelerating HER kinetics and increasing stability. Our catalyst delivers 1.0 A cm<sup>-2</sup> at an overpotential of 165 mV and sustains hydrogen production for more than 3000 h with negligible decay. When used as the cathode in a platinum-group-metal-free AEM water electrolyzer, it achieves a value of 2.0 A cm<sup>-2</sup> at 1.68 V, surpassing the DOE 2026 AEM benchmark of 2.0 A cm<sup>-2</sup> at 1.8 V, and operates for 1200 h at 1.0 A cm<sup>-2</sup> with a low degradation rate of 42.8 μV h<sup>-1</sup>.