Doping of Fe on room-temperature-synthesized CoNi layered double hydroxide as an excellent bifunctional catalyst in alkaline media

Abstract

Currently, the high demand for energy results in a large amount of pollution, which is of great concern. To overcome this problem, a highly active and low-cost bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial to satisfy industrial criteria. Layered double hydroxides (LDH) attracted significant interest in several fields, including catalysis, storage of energy, delivery of druges, etc. A simple coprecipitation method for the preparation of highly active electrochemical Fex/CoNi LDH catalysts at room temperature was described here. In alkaline media, from series of prepared catalysts, the Fe8%/Co–Ni LDH shows superior electrocatalytic activity with an overpotential of 232 mV at 10 mA/cm2, and Eo 91 V and E1/2 0.83 V versus RHE comparable to both noble metal-based and noble-metal-free OER/ORR catalysts recorded. Proper electronic structure and charging resistance that can facilitate the reduction of electron movement in the ORR/OER, are considered as two main factors in reducing the over-potential catalytic reaction.