Monometallic interphase synergistic Ni-based catalysts prepared by facile magnetron sputtering for efficient alkaline hydrogen evolution

The development of affordable, efficient and long-lasting electrocatalysts plays a vital role in advancing clean and renewable energy technologies. Ni-based materials have emerged as highly promising alternatives to noble metal for HER. However, existing Ni-based catalysts are generally constrained by complex composition, structure and preparation process, as well as poor stability caused by the weak bonding with the electrode substrate. Here, we prepared monometallic interphase synergistic Ni/NiO self-supported electrodes on Cu foam. The as-prepared Ni/NiO/CF-110 shows excellent HER activity, displaying a lower overpotential of 22 mV at 10 mA cm-2 and achieving nearly 100% Faradaic efficiency. Meanwhile, Ni/NiO/CF-110 exhibits robust stability, withstanding a chronopotentiometric test at 100 mA cm-2 over 100 h. The Ni/NiO/CF-110 was assembled into an alkaline electrolytic cell for water splitting, achieving 10 mA cm-2 with a remarkably low cell voltage of 1.4 V. The outstanding HER performance can be attributed to the synergistic effect of the monometallic phase Ni and NiO, the structural benefits of foam substrate, the good combination with substrate, and the optimal Ni/NiO ratio. This study proposes a novel and simple preparation strategy and provides guidance for developing highly efficient non-precious metal catalysts.