Ferric ions leached from Fe-based catalyst to trigger the dynamic surface reconstruction of nickel foam for high-efficient OER activity

The understanding of the interactions between catalyst and support is very important in heterogeneous catalysis of water splitting; however, it is still lacking. Herein, a Fe-based material of rod-like Fe₂OF₄ is fabricated as the oxygen evolution reaction (OER) electrocatalyst. Strikingly, Fe₂OF₄ loaded on nickel foam support can exhibit high-efficient OER activity with low overpotential and Tafel slope. Furthermore, we reveal that partial ferric ions within Fe₂OF₄ can leach out into electrolyte; and then the ferric ions are electrochemically adsorbed on the surface of nickel foam, triggering dynamic surface reconstruction to generate highly active FeNi-oxyhydroxides under alkaline OER condition. Further, based on our findings, a promising approach is successfully proposed to prepare a large-size, low-cost and high-performance OER electrode via surface reconstruction on NF with ferric ions, showing remarkable performance. This work provides new insights into catalyst-support interactions, and proposes a straightforward surface reconstruction strategy for the scaling-up of electrocatalysts.