The correlation of the nickel (1 1 1) facet with the hydrogen evolution performance of Ni electrodes in alkaline solutions

Abstract

Understanding the structural transformation and degradation mechanism of nickel (Ni) electrodes is beneficial for designing long-lasting and efficient hydrogen evolution reaction (HER) electrodes. Herein, the effects of applied current density and electrolysis time on the HER performance of Ni electrodes were systematically studied in alkaline solutions. After serving as a HER electrode, the intensity of XRD diffraction peak of the Ni (1 1 1) facet increased and the HER performance of the Ni electrode decreased. By reversing the applied current at the used Ni electrode, the intensity of XRD diffraction peak of the Ni (1 1 1) facet decreased, as well as the HER performance increased. Combing the surface change and the density functional theory (DFT) analysis, the HER performance of the Ni electrode was related to the intensity of Ni (1 1 1) facet that can be tuned by controlling hydrogen concentration at surface of Ni electrodes. Overall, this work reveals the relationships between the Ni (1 1 1) facet with its HER performance in alkaline solutions, offering insights into diagnosing and healing approaches for Ni-based HER electrodes.