Hydroxides-Derived Self-Supported Bimetallic Nickel–Cobalt Selenide Heterostructure for Alkaline Electrocatalytic Oxygen Evolution

Self-supported nonprecious metal selenide electrocatalysts have demonstrated significant potential for oxygen evolution reaction, due to stable spatial framework and extensive electrochemical interface. However, the design and construction of metal selenides, particularly heterostructures, continue to pose significant challenges. In this work, self-supported Ni–Co selenide heterostructures were successfully fabricated via a one-step selenization process utilizing the hydroxide precursor. The electrocatalytic performance of the composite was systematically examined, focusing on the influence of selenization temperature and the Ni/Co molar ratio. As expected, the optimal composite shows remarkable electrocatalytic performance in an alkaline environment, achieving an overpotential of merely 291 mV at 50 mA cm–2, surpassing numerous previously reported Co- and Ni-based electrocatalysts. Additionally, the electrocatalyst demonstrates exceptional cyclability and maintains its structural and compositional integrity even after stability testing.