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.