Transparent vanadium doped titania-silica films: Structural characterization and self-cleaning properties
Andraž Šuligoj, Nejc Povirk, Ksenija Maver, Andraž Mavrič, Urška Lavrenčić Štangar, Angelja Kjara Šurca
Abstract
Vanadium is one of the most promising dopants for titanium dioxide, as it has different oxidation states and comparable atomic sizes to titanium cation. In this article, vanadium-modified TiO 2 was prepared at low temperatures and immobilized on glass for self-cleaning and superhydrophilic purposes. The synthesis was carried out at 80 °C under reflux for 48 hours and only 150 °C was required for complete immobilization on the glass surface using silica binder, which in turn formed 120 nm thick films. Such multilayered (3) films showed enhanced transparency in the visible region of the spectrum and exhibited strong superhydrophilic properties (water contact angle, WCA < 5°) even when not illuminated. Vanadium was present in interstitial regions, while the unbound vanadium formed V 2 O 5 nanoparticles at higher concentrations. The presence of vanadium did not improve the photocatalytic properties for the degradation of fatty layers composed of stearic acid, which could be attributed to reduced migration of electrons and holes due to the trapping effects of vanadium species in such samples.