Direct Growth of CNTs@CoSxSe2(1−x) on Carbon Cloth for Overall Water Splitting

Abstract Searching for low‐cost, high‐efficiency, bifunctional, non‐noble‐metal electrocatalysts for overall water splitting is crucial to renewable energy conversion. Herein, a series of component‐controllable CC/CNTs@CoS x Se 2(1− x ) (CC: carbon cloth, CNT: carbon nanotube) with excellent bifunctional properties in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were obtained by chemical vapor deposition. In this strategy, the Zif‐67 precursor served as a structural inducer, which was directly grown on CC and pyrolyzed with the assistance of melamine to form multi‐walled CNT‐encapsulated CoS x Se 2(1− x ) hierarchical nanostructures. Subsequently, the electrocatalytic properties of the as‐prepared materials were optimized by adjusting the S/Se molar ratio. Of note is that the lattice distortion caused by the different radii of Se and S generated a polarized electric field for easy adsorption of the intermediate products. The CoOOH generated in situ on the surface of CoS x Se 2(1− x ) , as well as n‐ and p‐type domains in carbon, synergistically resulted in abundant active sites to boost the electrocatalytic activity. CC/CNTs@CoS 0.74 Se 0.52 exhibited overpotentials for the HER and OER of 225 and 285 mV, respectively and attained a current density of 10 mA cm −2 in alkaline solution. The as‐prepared electrocatalysts could act as both cathode and anode in a water electrolyzer showing a cell voltage of 1.74 V and delivering 10 mA cm −2 , comparable to those of noble‐metal‐based water electrolyzers.