Synthesis of nanostructured hollow microspheres of vanadium (III, V) oxides

Vanadium oxides V$_{2}$O$_{5}$ and V$_{2}$O$_{3}$ have been synthesized by ultrasonic spray pyrolysis in the form of nanostructured spherical agglomerates with an average diameter of 0.5–1.5 $\mu$m. By changing the synthesis conditions, the vanadium oxidation state and microspheres surface morphology can be varied. The microspheres of V$_{2}$O$_{5}$ are formed during aerobic synthesis, while V$_{2}$O$_{3}$ microspheres are produced under an atmosphere of argon. An increase in the concentration of the initial solution leads to an increase in both size of V$_{2}$O$_{5}$ nanoparticles and the diameters of the V$_{2}$O$_{5}$ microspheres. Long-term storage of V$_{2}$O$_{3}$ in air results in morphological degradation of the microspheres.