Symmetric synergy of hybrid CoS2–WS2 electrocatalysts for the hydrogen evolution reaction

Abstract

A highly active and stable hybrid electrocatalyst 3D hierarchical CoS₂ nanosheets incorporated with WS₂ (CoS₂@WS₂) has been developed via a one-step sulfurization method for the first time, where the contents of WS₂ can be adjusted easily. We first prove that the addition of small amounts of WS₂ enhances the hydrogen evolution reaction (HER) performance of CoS₂, and vice versa. In other words, we validated the symmetric synergy for the HER between the Co- and W-based sulfide hybrid catalysts. In addition, we confirmed that the formation of nanointerfaces of Co–S–W between CoS₂ and WS₂ was responsible for the excellent HER activity (an overpotential of −97.2 mV at −10 mA cm⁻², a small Tafel slope of 66.0 mV dec⁻¹, and prominent electrochemical stability) of the hybrid electrocatalyst CoS₂@WS₂.