Mechanically generating active nickel surface for promoting hydrogen evolution reaction.

Exploiting low-cost and high-activity catalysts is crucial for lowering energy consumption for hydrogen evolution reaction (HER). Herein, we reported a pure Nickel catalyst with high activity and long-term stability at a large current density in an alkaline medium. We employed an industrial machining technology, turning processing, to generate Ni-chips, a self-supported catalyst, with mostly close-packed planes exposed and high compressive strain. The close-packed plane and compressive strain jointly lower the d -band center of the nickel catalyst and overcome the excessive adsorption for reactive intermediates. As such, Ni-chip achieves ultralow overpotentials of 70 mV at 10 mA cm−2 and 297 mV at 1000 mA cm−2. Particularly, the catalyst exhibits outstanding stability at high current density (1 A cm−2), after working for one and a half months (ca. 1070 h), the initial current density merely declined by 7.3%. With its remarkable catalytic activity, excellent stability, ease of synthesis, and utilization of metallic scraps, the Ni-chip catalyst may serve as a promising catalyst for industrial applications. Ni-chip catalysts with high compressive strain and predominantly close-packed planes were prepared through turning processing. This combination effectively mitigated the excessive adsorption of *OH and *H on the Ni surface, enabling an ultralow overpotential of 297 mV at 1000 mA cm-2, and excellent stability at 1 A cm-2 for 1070 h, demonstrating potential as an efficient and durable electrocatalyst. [Display omitted] [ABSTRACT FROM AUTHOR]