A moderate method for in situ growing Fe-based LDHs on Ni foam for catalyzing the oxygen evolution reaction

Fe-based LDHs have been proven to be an excellent class of catalysts for the oxygen evolution reaction (OER). To achieve industrial applications of water splitting, it is critical to develop a cost-effective and simple strategy to achieve large-area catalytic electrodes. Herein, we present a moderate in situ method for growing Fe-based layered double hydroxide nanosheets on a Ni foam (LDH@NF) substrate at room temperature. Through systematic experimental design characterization, it is found that this in situ growth process is mainly driven by moderate oxidation of Fe²⁺ in an O₂-dissolved solution, the consequent local alkaline environment, and abundant TM²⁺ ions (Ni²⁺, Co²⁺, Ni²⁺/Co²⁺). Compared with other in situ methods, this method is not accompanied by violent redox reactions and is favorable for the uniform growth of LDHs, and the composition of the catalyst can be easily regulated. Specifically, the optimized NiFe-LDH@NF catalyst demonstrates excellent catalytic performance in the alkaline water oxidation reaction with a low overpotential of 206/239 mV at a current density of 10/100 mA cm^-2, respectively.