2D organ-like molybdenum carbide (MXene) coupled with MoS2 nanoflowers enhances the catalytic activity in the hydrogen evolution reaction

Abstract

Two-dimensional molybdenum carbides belong to a novel family of 2D transition metal carbides/nitrides called MXenes, which have a wide range of electrochemical applications. However, the synergistic catalysis of transition metal carbides and disulfides has not been studied in depth. A strategy was proposed to prepare a 2D organ-like Mo₂C MXene matrix derived from Mo₂Ga₂C crystals, coupled with MoS₂ nanoflowers to explore the hydrogen evolution reaction (HER) of molybdenum carbides and disulfides. Compared with Mo₂CT_x (where T_x means F, O, and OH surface terminations) Mxene catalysts, MoS₂@Mo₂CT_x nanohybrids showed significantly enhanced HER activity, with a low overpotential of 176 mV in alkaline media at a current density of 10 mA cm⁻² and a very small overpotential of 26 Ω. Density functional theory calculations indicated that the reduction of the hydrogen adsorption energy of the MoS₂@Mo₂CT_x nanohybrids could be attributed to fast electron transport ensured by Mo₂CT_x with intrinsic conductivity and a large number of hydrogen adsorption sites provided by MoS₂ nanoflowers. The synthetic method is promising to tailor the specific properties by preparing organ-like molybdenum carbides coupled with MoS₂ nanoflowers.