Structure-designed synthesis of hollow/porous cobalt sulfide/phosphide based materials for optimizing supercapacitor...

Cobalt-based transition metal phosphides/sulfides have been viewed as promising candidates for supercapacitor (SCs) and hydrogen evolution reaction (HER) featured with their intrinsic merits. Nevertheless, the sluggish reaction kinetics and drastic volume expansion upon electrochemical process hinder their commercial application. In this work, the hollow/porous cobalt sulfide/phosphide based nanocuboids (C-CoP₄ and CoS₂ HNs) with superior specific surface area are achieved by employing a novel chemical etching-phosphatization/sulfuration strategy. The hollow/porous structure could offer rich active sites and shorten electrons/ions diffusion length. In virtue of their structural advantage, the obtained C-CoP₄ and CoS₂ HNs perform superior specific capacitance, fast charge/discharge rate and beneficial cycling stability. The advanced asymmetrical supercapacitors assembled by C-CoP₄ and CoS₂ HNs deliver exceptional energy density, respectively. Furthermore, when employed as hydrogen evolution reaction electrocatalysts, C-CoP₄ and CoS₂ HNs yield favorable electrocatalytic activity. These findings shed fundamental insight on the design of dual-functional transition metal phosphide/sulfide based materials for optimizing hydrogen evolution reaction and supercapacitor storage properties.