WAN Weimin, WANG Min, CHEN Yongjun, LUO Lijie, YU Wanfei, ZHANG Yanping
(School of Materials Science and Engineering, State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, Hainan, China)
Abstract: NiFe layered double hydroxide (LDH)-based materials arouse great attention because of their outstanding catalytic activity for oxygen evolution reaction (OER) under alkaline conditions. However, their catalytic activity for hydrogen evolution reaction (HER) under alkaline conditions is not sufficiently high. Herein, Cd is used to dope NiFe-LDH nanosheet array by using hydrothermal method, to achieve high HER performance. In 1 M KOH solution, at a low overpotential of 111 mV, the current density could reach 10 mA·cm−2 for HER, with a low Tafel slope of 93.5 mV·dec−1. Simultaneously, when the NiFeCd-LDH is used as bifunctional catalysts, just a low voltage of 1.621 V is required to achieve a current density of 10 mA·cm−2. The outstanding catalytic performance is attributed to the increase density of Fe electron cloud, due to the Cd doping effect in NiFe LDH, which is conducive to the adsorption of protons. Meanwhile, Cd acts as a new active site for water adsorption, thus improving the performance of electrocatalytic hydrogen evolution.
Key words: NiFe LDH; Cd; doping; electrocatalytic hydrogen evolution; overall water splitting