Porous Molybdenum Carbide Nanostructures Synthesized on Carbon Cloth by CVD for Efficient Hydrogen Production.

Molybdenum carbide (Mo2 C) is a promising noble-metal-free electrocatalyst for the hydrogen evolution reaction (HER), due to its structural and electronic merits, such as high conductivity, metallic band states and wide pH applicability. Here, a simple CVD process was developed for synthesis of a Mo2 C on carbon cloth (Mo2 C@CC) electrode with carbon cloth as carbon source and MoO3 as the Mo precursor. XRD, Raman, XPS and SEM results of Mo2 C@CC with different amounts of MoO3 and growth temperatures suggested a two-step synthetic mechanism, and porous Mo2 C nanostructures were obtained on carbon cloth with 50 mg MoO3 at 850 °C (Mo2 C-850(50)). With the merits of unique porous nanostructures, a low overpotential of 72 mV at current density of 10 mA cm-2 and a small Tafel slope of 52.8 mV dec-1 was achieved for Mo2 C-850(50) in 1.0 m KOH. The dual role of carbon cloth as electrode and carbon source resulted into intimate adhesion of Mo2 C on carbon cloth, offering fast electron transfer at the interface. Cyclic voltammetry measurements for 5000 cycles revealed that Mo2 C@CC had excellent electrochemical stability. This work provides a novel strategy for synthesizing Mo2 C and other efficient carbide electrocatalysts for HER and other applications, such as supercapacitors and lithium-ion batteries.