Well-defined CoSe2@MoSe2 hollow heterostructured nanocubes with enhanced dissociation kinetics for overall water splitting
Hollow heterostructures have tremendous advantages in electrochemical energy storage and conversion areas due to their unique structure and composition characteristics. Here, we report the controlled synthesis of hollow CoSe2 nanocubes decorated with ultrathin MoSe2 nanosheets (CoSe2@MoSe2) as an efficient and robust bifunctional electrocatalyst for overall water splitting in wide pH range. It’s found that integrating the ultrathin MoS2 nanosheets with hollow CoSe2 nanocubes can provide abundant active sites, promote electron/mass transfer and bubble release and facilitate the migrations of charge carriers. Additionally, the surface electron coupling in the heterostructure enable it to serve as a source of sites for H+ and/or OH– adsorption, thus reducing the activation barrier for water molecules adsorption and dissociation. As a result, the titled CoSe2@MoSe2 hollow heterostructures exhibit an overpotential of 183 mV and 309 mV at a current density of 10 mA cm-2 toward hydrogen evolution reactions and oxygen evolution reactions in 1.0 M KOH, respectively. When applied as both cathode and anode for overall water splitting, a low battery voltage of 1.524 V is achieved along with an excellent stability for at least 12 h. This work provides a new idea to the design and synthesis of high-performance catalysts for electrochemical energy storage and conversion.