MoS₂@X₂C (X = Mo or W) hybrids for enhanced supercapacitor and hydrogen evolution performances

Engineering the active sites is a promising approach to boost electrode enactment for various electrochemical applications. Herein, highly conductive Mo₂C and W₂C were interfaced with the layered MoS₂ as the efficient material for symmetric supercapacitors and water splitting. For the first time, systematically fabricated MoS₂@Mo₂C and MoS₂@W₂C hybrid supercapacitor electrodes explored the excellent specific capacitance of 1040 and 681 F.g⁻¹ at 0.5 A.g⁻¹ current density, respectively, and robust long-term cycling in the half-cell measurements. Moreover, the customized symmetric supercapacitors using MoS₂@Mo₂C electrode showed a 349 F.g⁻¹ capacitance at 0.5 A.g⁻¹ current density with a maximum energy density of 48 Wh.kg⁻¹ at 0.25 kW.kg⁻¹ power density. MoS₂@Mo₂C hybrid hydrogen evolution catalysts produced the low overpotentials and small Tafel slopes in the acidic and alkaline media which ascertained their plentiful edges and high conductance. Density functional theory calculations disclosed that incorporation of X₂C (X = Mo or W) with the layered MoS₂ can be improved to acquire more ideal energy for adsorption of hydrogen at the catalyst surface. The proposed strategy of metal carbides blended layered metal chalcogenides proved their expertise by hypothetical and experimental results, could be created the new platform to extend their uses for various future energy applications.