β-Mo2C nanoparticles/carbon nanotubes Mott-Schottky nanoarray on carbon cloth as freestanding cathodes for efficient hydrogen evolution reaction

Developing efficient non-noble metal-based electrocatalysts for the hydrogen evolution reaction (HER) is urgently required for the large-scale electrolysis of water. Mo2C shows excellent HER catalytic activity. The construction of heterostructures by combining Mo2C and carbonaceous materials provides an effective strategy to modulate the electronic structure and hydrogen adsorption ability of molybdenum carbide. The β-Mo2C nanoparticles bundled on semiconducting carbon nanotubes (CNTs) with a Mott-Schottky heterojunction has been prepared in situ on the carbon cloth via a facile solvothermal and annealing process. Contributing to the synergistic effect of β-Mo2C and CNTs, the synthesized Mo2C/CNTs@CC electrode exhibits greatly enhanced HER catalytic activity with an overpotential of 123 mV to achieve a current density of −10 mA cm−2, a Tafel slope of 51 mV dec−1, and excellent durability. DFT calculations indicate that the CNTs donate electrons to β-Mo2C to enhance the coupling interfaces within β-Mo2C and CNTs and modify the electronic structure, resulting in a lower reaction barrier in the Volmer step and faster HER activities. This work provides a synthetic route to Mott-Schottky heterostructure Mo2C/CNTs with excellent HER catalytic activity.