Influence of nitric acid peptization on the band gap of sol gel derived, nanostructured titania.

摘要

Nanostructured anatase-phase titanium dioxide was prepared by sol gel synthesis, peptized with several concentrations of nitric acid (H+ :Ti4+ ratio of 0, 0.5, 0.75, or 1.0), and calcinated at 80, 300, 400, or 500 °C. The band gap, measured using UV-vis, was observed to decrease non-linearly with respect to concentration and temperature. The minimum band gap occurred at a H+:Ti4+ ratio of 0.5 and a temperature of 500 °C. FTIR spectra indicate that peptization leads to the incorporation of nitrogen species into the lattice at 80 and 300 °C. The rutile fraction was calculated from XRD data, and ranged from 0 to 57 %. These two factors partially explain band gap variations.