Deep reconstruction of highly disordered iron/nickel nitrate hydroxide nanoplates for high-performance oxygen evolution reaction in alkaline media

Rational design of FeNi based electrocatalysts with robust OER activity and stability is of great significance for promising water electrolysis. In this work, in-situ growth of highly disordered iron-nickel nitrate hydroxide (FeNiNH) nanoplates on nickel foam via a simple one-pot solvothermal method is demonstrated. The highly disordered FeNiNH exhibits coexistence of amorphous and crystal microstructure, providing more active sites from boundaries, while Fe incorporation improves the electronic structure, indeed accelerating intrinsic activity. The optimized Fe₁Ni₉NH shows high electrocatalytic activity with a low overpotential of 209 mV at 50 mA/cm², a Tafel slope of 73 mV/dec and good long-term stability. Deep phase transformation from FeNi nitrate hydroxide to FeNi oxyhydroxide can be discovered with nitrate leaching during OER process. Our work provides a novel strategy for the design of efficient OER electrocatalyst and a new sight in the reconstruction process for FeNi based electrocatalysts.