A Highly Active CoFe Layered Double Hydroxide for Water Splitting.

Highly active, cost-effective, and durable catalysts for oxygen evolution reaction (OER) are required in energy conversion and storage processes. A facile synthesis of CoFe layered double hydroxide (CoFe LDH) is reported as a highly active and stable oxygen evolution catalyst. By varying the concentration of the metal ion precursor, the Co/Fe ratios of LDH products can be tuned from 0.5 to 7.4. The structure and electrocatalytic activity of the obtained catalysts were found to show a strong dependence on the Co/Fe ratios. The Co2 Fe1 LDH sample exhibited the best electrocatalytic performance for OER with an onset potential of 1.52 V (vs. the reversible hydrogen electrode, RHE) and a Tafel slope of 83 mV dec-1 . The Co2 Fe1 LDH was further loaded onto a Ni foam (NF) substrate to form a 3D porous architecture electrode, offering a long-term current density of 100 mA cm-2 at 1.65 V (vs. RHE) towards the OER.