Surfactant-assisted hydrothermal synthesis of nitrogen doped Mo2C@C composites as highly efficient electrocatalysts for hydrogen evolution reaction

Abstract

We describe a facile surfactant-assisted hydrothermal route to synthesize nitrogen doped Mo2C@C composites in the presence of cetyltrimethylammonium bromide (CTAB) as carbon source and structure guiding agent. The resulting Mo2C@C composites consist of Mo2C nanocrystals with sheet-like morphology and well-dispersed nitrogen element doping. Controllable experiments indicate that the additive amount of CTAB can efficiently tune porous structure and electrochemical activity of the as-prepared Mo2C@C materials. This unique nitrogen doped Mo2C@C composite provides several advantages for electrocatalytic applications: (1) nitrogen doped carbons can prevent the aggregation of Mo2C nanocrystals and render it high conductivity; (2) the homogeneous dispersion of Mo2C nanocrystals provides abundant active sites; (3) 2D morphology, the hierarchical porosity, and high surface areas allow large exposed field of active sites and facilitate mass transfer. As a result, the nitrogen doped Mo2C@C composites deliver superior HER electrocatalytic activities with a low overpotential of only 100 mV and also a low Tafel slope of 53 mV/dec in alkaline condition. Such CTAB-assisted strategy may open up an opportunity towards synthesis of low cost and high performance Mo-based electrocatalysts for various applications, such as water splitting.