Vanadium Carbide Nanoflakes as Catalysts for V3+/V2+ Redox Reactions

Vanadium carbide nanoflakes were synthesized and investigated as catalysts for V³⁺/V²⁺ redox reaction. This work explored a simple and environmentally friendly synthesis process that involved in situ carburization of a metal precursor and a carbon material as the carbon source and support. The structure, composition, morphology, and thermal stability of the vanadium carbide nanoflakes were characterized by X-ray diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Vanadium carbide supported on Vulcan XC72 carbon black showed a smaller particle size than that on graphite. Electrochemical properties of vanadium carbide nanoflakes toward the V³⁺/V²⁺ redox reaction were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The results show that vanadium carbide nanoflakes exhibited significantly enhanced catalytic activities and reversibility than graphite toward the V³⁺/V²⁺ redox reaction.