One-step hydrothermal synthesis and characterization of V–Cr–O nanospheres and their excellent performance in the ammoxidation of 3,4- and 2,6-DCT

Graphical abstract: - Highlights: • V–Cr–O composite was synthesized by a facile one pot hydrothermal route. • The V–Cr–O composite has sphere-like morphology. • The as-obtained V–Cr–O composite has large specific surface area: 117 m² g⁻¹. • V–Cr–O complex was explored as the catalyst for the ammoxidation. - Abstract: Sphere-like V–Cr–O catalyst was successfully synthesized using V₂O₅, CrO₃ and H₂C₂O₄ solution as the starting materials by a facile one pot hydrothermal approach for the first time. The as-obtained samples were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectrometer, hydrogen temperature programmed reduction, scanning electron microscopy and Brunauer–Emmett–Teller. The results indicated that V–Cr–O spheres with the diameter about 4 μm, consisted of lots of nanoparticles, were formed. The as-obtained V–Cr–O catalyst had large specific surface area: 117 m² g⁻¹. Furthermore, V–Cr–O complex was explored as the unsupported catalyst for the synthesis of 3,4- and 2,6-dichlorobenzonitrile by the ammoxidation of 3,4- and 2,6-dichlorotoluene. It was found that it had excellent performance in the ammoxidation reactions, specially, the catalytic temperature was decreased to about 320 °C, which was much lower than the previous reports (380–420 °C)