Strong electronic coupling between Ni-based MOF and Ni2P enables high-efficiency oxygen evolution reaction for various application scenarios

The high overpotential and sluggish kinetics of oxygen evolution reaction (OER) severely hinder the widespread application of electrochemical water splitting, especially at industrial-level current densities. Herein, we report a novel heterostructural Ni-based metal organic framework (MOF)-Ni 2 P in-situ grown on iron foam (NiMOF-Ni 2 P/IF), which shows remarkable OER activity and stability. We demonstrate that the work function difference between NiMOF and Ni 2 P leads to the strong electron coupling effect by promoting electron transfer at the interface and results in a discernible upward shift of the d-band center of Ni sites for favorable OH − adsorption. The as-fabricated NiMOF-Ni 2 P/IF exhibits an ultralow overpotential of 330 mV and a small cell voltage of 1.796 V to drive NiMOF-Ni 2 P/IF‖Pt/C system at 1000 mA cm −2 in 1 M KOH, outperforming the majority of state-of-the-art non-noble-metal-based electrocatalysts. Furthermore, the catalyst shows remarkable performance even under harsh industrial conditions of 40, 60, and 80 °C in 6 M KOH. In addition, NiMOF-Ni 2 P/IF holds great promise with remarkable stability of 200 h and 600 cycles in simulated seawater and secondary zinc-air batteries (ZABs), respectively. This work offers a rational design strategy for low cost, high activity, and long durability OER electrocatalyst based on in-depth comprehension of the electronic coupling effect.