Crystalline state transformation strategy for improving the catalytic performance of oxygen evolution reaction at high current density

Because the oxygen evolution reaction (OER) greatly limits the large-scale application of electrolyzed water, it is crucial to develop and synthesize effective electrocatalysts. Herein, we report a solvent substitution strategy to prepare the iron-naphthalenedicarboxylic acid (Fe-NDC) coordination complex. Through the crystalline state transformation of Fe-NDC from the crystalline to the amorphous phase, the catalytic performance of the prepared catalyst for OER at high current density can be significantly improved under alkaline conditions. Profiting from exposed metal active sites and expanded electron transport channels, amorphous-phase Fe-NDC (AP-Fe-NDC) exhibits stable electrocatalytic activity, with 225 and 333 mV overpotentials at 10 and 500 mA/cm2, respectively. Moreover, AP-Fe-NDC displays high oxygen yield and faraday efficiency. This rapid and facile strategy will be of immediate benefit to guide the preparation of other high-performance and low-cost OER catalysts.