Ultrafast fabrication of nanospherical CoFe alloys for boosting electrocatalytic water oxidation

Developing a facile method for fabricating low-cost electrocatalysts to achieve high activity and stability toward oxygen evolution reaction (OER) becomes increasingly significant and urgent, due to the increasing consumption of non-renewable energy and consequent environmental problems. Herein, we demonstrate an ultrafast one-step potentiostatic electrodeposition method to fabricate advanced self-supporting CoFe alloy nanocatalysts for OER with only 40 s. The self-supporting CoFe alloys not only have unique pore channels for facilitating electrolyte diffusion and O2 releasing, but also possess high electrical conductivity for efficient charge transport. More importantly, rich amorphous area can continuously provide more active sites and a higher intrinsic activity of such sites. As a result, the optimized CoFe4:1 only needs the overpotential of 275 mV to achieve 10 mA cm−2 and small Tafel slope of 67.1 mV dec−1 in 1.0 M KOH. More importantly, the CoFe4:1 can also display outstanding durability with ignorable variation after CP test for 130 h. Furthermore, by correspondingly combining CoFe4:1 and Pt/C as an anode and a cathode for driving overall water splitting, a cell potential of only 1.60 V is required to achieve a current density of 10 mA cm−2, outperforming the state-of-the-art RuO2 ‖Pt/C couple.