Ternary FeCo₂Mo₅ Oxyhydroxide Nanosheets Integrate on the Surface-Vulcanized Ni Foam for Excellent Electrocatalytic Oxygen Evolution

Earth-abundant first-row transition-metal-based electrocatalysts with a large current density for water splitting are pivotal to give impetus to large-scale utilization of hydrogen energy. However, the operating potential is significantly larger than the thermodynamic requirements. Herein, the ternary FeCo₂Mo₅ layered double hydroxide (LDH) nanosheets grown on the surface of a vulcanized Ni foam (FeCo₂Mo₅ LDH/Ni₃S₂/NF) are proposed to improve the mass and electron transport for driving the oxygen evolution reaction (OER), where the integrated hierarchical structure configurations contribute rich active sites and a large electrode/electrolyte interface for mass transfer, and the construction of a Ni₃S₂/NF heterojunction can facilitate electron mobility from the surface to the inner region, leading to a high valence of FeCo₂Mo₅ LDH with favorable OER kinetics. Therefore, the catalyst exhibits excellent OER activity with the ultralow overpotential of 128 and 300 mV at the current density of 10 and 100 mA cm^–2 in 1 M KOH and activity retention over 12 h at 95 mA cm^–2. This research may enable a large extension toward the design of cheap and highly efficient practical catalytic electrodes for water splitting.