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

•Simple reaction process employed to synthesis the MoS2@Mo2C and MoS2@W2C hybrid.•Hydrogen evolution explored the low overpotential and Tafel slope in base and acid.•High specific capacitance of 1040 Fg−1 @ 0.5 A.g−1 with better rate capability.•Symmetric capacitor exposed 349 F.g−1 at 0.5 A.g−1 with 97 Wh.kg−1 at 0.5 kW.kg−1.•First principle DFT calculation derived the superior catalytic behavior in MoS2@Mo2C. 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.