CoS2 Yolk-Shell Spheres Coated with Carbon Thin Layers as High Active and Stable Electrocatalysts for Hydrogen Evolution Reaction

摘要

Though water electrolysis is effective in generating high-quality hydrogen gas,it requires effective electrocatalysts for hydrogen evolution reaction (HER).CoS2 have been considered as a promising HER electrocatalyst because of its high ctalytic activity.However,the key limitation for CoS2 nanomaterial as HER electrocatalyst is its poor stability,which may be due to the structural breakdown of CoS2 nanostructure or the evolution of S during H2 evolution in acid media.Coating porous carbon thin layer for protection from structural breakdown and evolution of S is a good way to improve catalytic stability.In addition,coating carbon layer can change electronic structure of CoS2 for the moderated hydrogen adsorption energy,leading to enhanced catalytic activity.Here,CoS2 yolk-shell spheres coated with carbon thin layers exhibit superior catalytic performance for HER with low overpotential,small Tafel slope,and excellent stability.