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 Co2Fe1 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 Co2Fe1 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. Simple and efficient: A highly active CoFe layered double hydroxide (LDH) was prepared by co‐precipitation and then coated on a Ni foam (NF) by self‐assembly. The CoFe LDH/NF with 3D porous structure exhibits excellent performance toward the oxygen evolution reaction OER, holding great promise for water splitting.