In situ grown core-shell-like CoMoP@CoxNiyP hierarchical heterostructure on nickel foam as a stable bifunctional electrocatalyst for alkaline overall water splitting

Developing efficient, low-cost non-noble metal bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is critical for alkaline overall water splitting. Herein, a core-shell-like CoMoP@Co x Ni y P/NF heterostructure was fabricated via a two-step hydrothermal method followed by vapor-phase phosphorization and was in situ grown on three-dimensional porous nickel foam. The hierarchical architecture combines CoMoP nanorods with Co x Ni y P nanosheets in a core-shell-like arrangement, providing increased accessible surface area, improved interfacial charge transfer, and regulated electronic structure. The catalyst delivers low overpotentials of 74.1 mV (HER) and 230.3 mV (OER) at 10 mA cm −2 in 1.0 M KOH. The assembled electrolyzer achieves a cell voltage of 1.51 V at 10 mA cm −2 with stable operation for 150 h at 50 mA cm −2 , providing insights into heterostructure engineering of bifunctional electrocatalysts for alkaline water splitting.