Suppressing deactivation in alkaline seawater oxygen evolution with Fe-doping induced dual-phase lattice strain in Ni/Mo nitrides

Seawater splitting provides a sustainable approach for large-scale hydrogen production without straining freshwater resources. However, the challenge lies in achieving high catalytic activity and stability due to electrocatalyst deactivation from structural degradation, poor corrosion resistance, and surface instability in both alkaline and seawater electrolysis. To address this, we propose a novel strategy combining Fe-doping with dual-phase lattice strain engineering in nickel-molybdenum transition metal nitrides (TMNs). The Fe-doped Ni 3 Mo 3 N/Mo 2 N electrocatalyst exhibits compressive lattice strains of −4.52% and −2.91% in the Ni 3 Mo 3 N and Mo 2 N phases, respectively, enhancing its structural integrity and electronic properties. Consequently, Fe-Ni 3 Mo 3 N/Mo 2 N achieves low overpotentials of 167 and 371 mV at current densities of 10 and 500 mA cm −2 , respectively, in 1 M alkaline seawater, with exceptional stability over 100 h at 100 and 500 mA cm −2 . Theoretical calculations reveal that these compressive strains optimize the adsorption of OER intermediates and improve catalytic kinetics. This work demonstrates the promise of dual-phase lattice strain engineering in TMNs for efficient, durable, and scalable electrocatalysts in seawater electrolysis, a strategy that has yet to be fully explored for OER.