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

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 95 mV and 44 mV decade⁻¹, respectively with the excellent electrocatalytic stability over 20 h. 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.