Carbonitride MXene Ti3CN(OH)x@MoS2 hybrids as efficient electrocatalyst for enhanced hydrogen evolution

Renewable energy powered electrocatalytic water splitting is a promising strategy for hydrogen generation, and the design and development of high-efficiency and earth-abundant electrocatalysts for hydrogen evolution reaction (HER) are highly desirable. Herein, MoS2 nanoflowers decorated two-dimensional carbonitride-based MXene Ti3CN(OH)(x) hybrids have been constructed by etching and post-hydrothermal methods. The electrochemical performance of the as-obtained Ti3CN(OH)(x)@MoS2 hybrids having a quasi core-shell structure is fascinating: An overpotential of 120 mV and a Tafel slope of 64 mV.dec(-1) can be delivered at a current density of 10 mA.cm(-2). And after 3,000 cyclic voltammetry cycles, it can be seen that there is no apparent attenuation. Both the experimental results and density functional theory (DFT) calculations indicate that the synergetic effects between Ti3CN(OH)(x) and MoS2 are responsible for the robust electrochemical HER performance. The electrons of -OH group in Ti3CN(OH)(x) are transferred to MoS2, making the adsorption energy of the composite for H almost vanish. The metallic Ti3CN(OH)(x) is also beneficial to the fast charge transfer kinetics. The construction of MXene-based hybrids with optimal electronic structure and unique morphology tailored to the applications can be further used in other promising energy storage and conversion devices.