CoS<sub>2</sub> Nanoparticles Embedded in Covalent Organic Polymers as Efficient Electrocatalyst for Oxygen Evolution Reaction with Ultralow Overpotential
Qian Ma, Rongfeng Liao, Yuheng Lu, Shaohong Liu, Youchen Tang, Youlong Zhu, Dingcai Wu
Abstract
Abstract Cobalt disulfide (CoS 2 ) has been explored as attractive electrocatalyst for oxygen evolution reaction (OER). However, bulk CoS 2 sheets have limited catalytic activity due to low exposure of active sites. Herein, through an in‐situ vulcanization approach, CoS 2 nanoparticles are embedded into bipyridine‐containing covalent organic polymer (BP‐COP). The as‐prepared nanocomposite CoS 2 @BP‐COP exhibits high catalytic activity toward OER with an ultra‐low overpotential of 270 mV (vs. RHE) at a current density of 10 mA cm −2 , a small Tafel slope of 36 mV dec −1 , and an excellent durability for 24 h without decay. The surface of CoS 2 is partially converted into CoOOH to form CoS 2 /CoOOH as active sites under OER conditions. CoS 2 @BP‐COP displays superior OER catalytic activity to CoS 2 nanosheets and commercially available RuO 2 under the same conditions. The outstanding OER performance activity of CoS 2 @BP‐COP could be attributed to the uniform and small particle sizes of CoS 2 /CoOOH distributed in BP‐COP.