Abstract
In this study, a VO₂@Fe₂O₃–TiO₂ nanocomposite was synthesised via an in-situ heat-assisted
sol-gel method and compared to a Fe₂O₃–TiO₂ nanocomposite for enhanced self-cleaning
performance. Titanium (IV) isopropoxide was used as a precursor for TiO2, while Ferric nitrate
and Vanadium (V) oxide were employed as sources of Fe₂O₃ and the VO₂ dopant, respectively.
The elemental composition analysis revealed the exclusive presence of Ti, O, Fe, and V,
showing successful synthesis of the material without impurities. The X-ray diffraction results
showed that VO2 doping led to some structural modifications that translated into better
crystallinity, while the BET analysis demonstrated a significant increase in specific surface area
of 40.643 m2/g and pore volume of 0.4286cm3, enabling the formation of more active sites for
photocatalytic activities. Optical studies demonstrated a band gap reduction from 2.86 eV
(Fe₂O₃–TiO₂) to 2.00 eV (VO₂@Fe₂O₃–TiO₂), indicating enhanced visible light-harvesting
capabilities. The samples were tested for the photodegradation of methylene blue under visible
light. VO₂@Fe₂O₃–TiO₂ showed enhanced photocatalytic degradation abilities by degrading
88.81% of the MB in 120 minutes compared to 15.84% for Fe₂O₃–TiO₂. Furthermore, the
electrochemical analyses and the band edge calculations indicated that the addition of VO2
improved the charge transfer kinetics, lowered the charge transfer resistance, enhanced
interfacial charge separation, and mediated a Z-scheme mechanism in which highly reactive
carriers were preserved by recombination of weak reactive ones, enabling the formation of
active radicals to improve the photocatalytic process. This study highlights the promise of
VO₂@Fe₂O₃–TiO₂ as an efficient photocatalyst for photocatalytic and self-cleaning
applications.