Efficient Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate over V₂O₅/g-C₃N₄ Catalysts

Graphitic carbon nitride (g-C₃N₄)-supported V₂O₅ catalysts were prepared by the impregnation pyrolysis method, and their physicochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV-vis, TGA, N₂ adsorption, and H₂-TPR. These catalysts exhibit extremely high activity and selectivity in the aerobic oxidation of ethyl lactate to ethyl pyruvate. The excellent catalytic performance derives from the high surface-chemisorbed oxygen species. Low calcination temperature and interaction with g-C₃N₄ are conducive to increasing the surface-chemisorbed oxygen species of V₂O₅. The optimal catalyst 13V₂O₅/g-C₃N₄ gives 96.2% conversion of ethyl lactate with 85.6% selectivity toward ethyl pyruvate in 4 h at 130 °C and 1 atm oxygen, which is significantly superior to those of previously reported V-containing catalysts. This catalyst is also stable and reusable, and the ethyl pyruvate yield is reduced by less than 10% after four runs without any regeneration treatment.