WS2/CoSe2 heterostructure: A designed structure as catalysts for enhanced hydrogen evolution performance

WS2/CoSe2 hybrid structure was implemented to enhance HER electrocatalytic activity. The WS2/CoSe2 catalyst exhibited low overpotentials of 95mV (@1mAcm−2) and 160mV (@ 10mAcm−2), a high exchange current density of ∼1.0×10−2mAcm−2, and a small Tafel slope of 44mVdecade−1. In addition, WS2/CoSe2 hybrid electrode was stable over 20h of sustained hydrogen production in 0.5M H2SO4 acidic medium. [Display omitted] The development of hydrogen-evolving catalysts based on transition metal dichalchogenides (TMDs) is receiving a great attention for practical application of water-splitting devices and fuel cells due to their high electrocatalytic activity. Herein, we synthesized tungsten disulfide (WS2)/cobalt diselenide (CoSe2) hybrid catalyst for hydrogen evolution reaction (HER). CoSe2 films were first deposited via electrodeposition of Co and followed by selenization process. And, the surface of the synthesized CoSe2 films was covered with WS2 via combined process of sputtering and sulfurization. In acidic media, the WS2/CoSe2 heterostructure catalyst exhibited fast hydrogen evolution kinetics of onset potential and Tafel slope were at 95mV and 44mVdecade−1, respectively with the excellent electrocatalytic stability over 20h. WS2/CoSe2 heterostructure electrode demonstrates an excellent HER activity and long-term stability owing to their abundant active edge sites, and the strong chemical and electronic coupling between the CoSe2 and WS2.