Construction of Ferric-Oxide-Doped Nickel-Iron Hydroxide Electrocatalysts by Magnetic-Field-Assisted Chemical Corrosion toward Boosted Oxygen Evolution Reaction.

Transition-metal-based oxygen evolution reaction (OER) catalysts have attracted widespread attention due to their inexpensive prices, unique layered structures, and rich active sites. Currently, designing low-cost, sustainable, and simple synthesis methods is essential for the application of transition-metal-based catalysts. Here, magnetic field (MF)-assisted chemical corrosion, as a novel technology, is adopted to construct superior OER electrocatalysts. The produced Ni(Fe)(OH) 2 -Fe 2 O 3 electrode exhibits an overpotential of 272 mV at a current density of 100 mA cm -2 , presenting a 64 mV reduction compared to the electrode without an MF. The experimental results indicate that an MF can induce the directional growth of Fe 2 O 3 rods and reduce their accumulation. In addition, an external MF is beneficial for the lattice dislocation of the obtained catalysts, which can increase the surface free energy, thus reducing the activation energy and accelerating the electrochemical reaction kinetics. This work effectively combines a magnetic field with chemical corrosion and electrochemical energy, which offers a novel strategy for the large-scale development of environmentally friendly and superior electrocatalysts.