Co-doped NiSe synthesized on solid-phase boronized self-supported NFF-B as a bifunctional electrocatalyst enables efficient and stable overall water splitting

Designing low-cost, efficient, and durable bifunctional electrocatalysts can significantly reduce the cost of industrial electrolysis of water. In this article, a novel self-supported nickel–iron foam completely covered with Ni 2 B particles was prepared through a solid-phase boronization method as the substrate (referred to as NFF-B). Then, an independent columnar Co-doped NiSe electrocatalyst composed of petal-shaped nanosheets was synthesized on NFF-B via a stirring-electrodeposition method. For comparison, a series of reference samples were also synthesized using the same process. The synthesized Ni 0.5 Co 0.5 Se/NFF-B exhibited excellent bifunctional catalytic activity and stability, with an HER overpotential of 90 mV and an OER overpotential of only 182 mV in 1 M KOH at 10 mA‧cm −2 . More importantly, the assembled Ni 0.5 Co 0.5 Se/NFF-B||Ni 0.5 Co 0.5 Se/NFF-B overall water splitting system required only 1.49 V to drive the electrolysis of water at 10 mA‧cm −2 , maintaining exceptional stability for 115 h under these conditions, surpassing most previously reported bifunctional electrocatalysts. Our work offers a new strategy for preparing efficient and durable bifunctional electrocatalysts.