Morphology Control of Hydrogen Evolution Reaction Catalyst Promoting H<sub>2</sub> Mass Transfer.

Lin, Gaoxin; Dong, Anrui; Li, Zhiheng; Wang, Linqin; Sun, Licheng · Nano Lett · 2026

basic_science · Level V

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Abstract

Gas bubble accumulation during hydrogen evolution reaction (HER) hinders mass transfer and limits ampere-scale performance, making the optimization of electrode microstructures for efficient H<sub>2</sub> release a critical challenge. We precisely synthesized NiMo/MoO<sub>2</sub>-based catalysts in 1D nanorod (1D-NR), 2D nanosheet (2D-NS), and 3D nanosheet-rod complex (3D-SR) structures to identify the optimal structure for enhanced HER mass transfer. The 1D-NR with the open-channel structure and a small adhesive force exhibited the lowest bubble detachment time (200 ± 40 ms) and the lowest potential fluctuation. In an anion exchange membrane water electrolyzer, a 1D-NR-catalyzed device suppressed slug and annular flow, allowing bubble flow to predominantly occupy the central region of the channels at high current. The 1D-NR-catalyzed device achieved 1.87 A cm<sup>-2</sup> at 1.8 V, representing 96.8% and 30.8% improvements over the 2D-NS and 3D-SR catalyzed devices, respectively. Moreover, the 1D-NR-catalyzed device showed long-term stability of 1400 h at 1 A cm<sup>-2</sup>.