One-step electrodeposition of cauliflower-like CozNiySx@polypyrrole electrocatalysts on carbon fiber paper for hydrogen evolution reaction.

Transition-metal chalcogenides as the promising alternatives to noble-metal-based electrocatalysts for hydrogen evolution reaction (HER) with high activity and durability in water splitting have attracted extensive attention in recent years. Herein, Co z Ni y S x @PPy composites with three-dimensional (3D) cauliflower-like were firstly prepared on carbon fiber paper (CFP) via a simple and efficient electrochemical reduction of elemental sulfur in the precursor of S@PPy composite coated on CFP to react with Co and Ni ions in the electrolyte. The optimum electrode, i.e., Co z Ni y S x @PPy/CFP-6 (A-6) prepared by using an electrolyte with a Co/Ni molar ratio of 0/6, showed excellent catalytic activity (with an overpotential of 185 mV@10 mA cm−2 and a small Tafel slope of 78.13 mV dec−1) as well as long-term stability (at least 100 h) in 1 M KOH solutions. This work provides a novel way to fabricate effective and non-noble-metal electrodes for HER in water splitting. Image 1 • An electrochemical reduction of sulfur way is used to prepare the TMCs. • The relationship of nickle and cobalt in the volcano plot is proved by experiment. • The mixed crystals of Ni y S x strengthen catalytic activity and stability of HER. [ABSTRACT FROM AUTHOR]