Symmetric synergy of hybrid CoS<inf>2</inf>-WS<inf>2</inf> electrocatalysts for the hydrogen evolution reaction

Abstract

A highly active and stable hybrid electrocatalyst 3D hierarchical CoS nanosheets incorporated with WS (CoS @WS ) has been developed via a one-step sulfurization method for the first time, where the contents of WS can be adjusted easily. We first prove that the addition of small amounts of WS enhances the hydrogen evolution reaction (HER) performance of CoS , 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 CoS and WS was responsible for the excellent HER activity (an overpotential of -97.2 mV at -10 mA cm , a small Tafel slope of 66.0 mV dec , and prominent electrochemical stability) of the hybrid electrocatalyst CoS @WS . 2 2 2 2 2 2 2 2 2 2 2 -2 -1