Ultrafine cobalt selenide nanowires tangled with MXene nanosheets as highly efficient electrocatalysts toward the hydrogen evolution reaction.

Hydrogen energy has attracted sustainable attention in the exploitation and application of advanced power-generator devices, and electrocatalysts for the hydrogen evolution reaction (HER) have been regarded as one of the core components in the current electrochemical hydrogen production systems. In this work, a facile and cost-effective bottom-up strategy is developed for the construction of 1D ultrafine cobalt selenide nanowires tangled with 2D Ti 3 C 2 T x MXene nanosheets (CoSe NW/Ti 3 C 2 T x ) through an in situ stereo-assembly process. Such an architectural design endows the hybrid system not only with a large accessible surface for the rapid transportation of reactants, but also with numerous exposed CoSe edge sites, thereby generating substantial synergic coupling effects. The as-derived CoSe NW/Ti 3 C 2 T x hybrid demonstrates competitive electrocatalytic properties toward the HER with a small onset potential of 84 mV, a low Tafel slope of 56 mV dec -1 and exceptional cycling performance, which are superior to those of bare CoSe and Ti 3 C 2 T x materials. It is believed this promising nanoarchitecture may provide new possibilities for the design and construction of precious-metal-free electrocatalysts with high efficiency and great stability in the energy-conversion field.