One-pot synthesis of etched CoMn-layered double hydroxides efficient for oxygen evolution reaction

Abstract

One-pot synthesis of etched thin CoMn-layered double hydroxides (LDHs) is successfully achieved via the in-situ ammonium fluoride etching at room temperature. The facile methodology developed here avoids the traditionally hydrothermal treatment and the complex exfoliation procedure. The as-prepared etched CoMn-LDHs of ~9.3 nm exhibit excellent performance in the oxygen evolution reaction, whereas the etched CoMn-LDHs display a reduction of 150 mV overpotential at 10 mA cm−2 compared to the state-of-the-art RuO2 in 0.1 M NaOH. Besides, the etched CoMn-LDHs display much smaller Tafel slope and resistance than that of non-etched CoMn-LDHs. Compared with the traditional method, the as-developed in-situ chemical etching is much more efficient with additional advantages of producing highly active sites. More importantly, density functional theory (DFT) has confirmed the experimental results and documented that the much enhanced electrocatalytic activity of thin CoMn-LDHs is associated with a nearly optimal intermediates (*OH and *O) adsorption energy.