Structure, morphology, and band gap of Ti-V-O mixed oxides processed by coprecipitation and calcination

Mixed oxides of Ti-V-O were co-precipitated by wet process using TiCl₄ and VOCl₃ as starting materials. As-precipitated gels were calcinated at 800°C for 4 hours in oxygen atmosphere. Effects of vanadium content on the structural evolution, morphology, and band gap of Ti-V-O oxides were investigated. Calcination has produced mixtures of TiO₂/VO₂/V₂O₅ oxides and has allowed formation of Ti_{1-x}V_{x}O₂. Lattice parameters of rutile TiO₂ were precisely measured to investigate vanadium substitution into single rutile phase of Ti_{1-x}V_{x}O₂ with varying vanadium content. As vanadium addition was increased, particles were coarsening rapidly during calcination. Band gap of the Ti-V-O oxides was measured using ultraviolet visible light spectrometer. A decrease of band gap down to 1.7 eV with the addition of maximum of 10 at.% of vanadium was measured, which is due to the formation of single phase of Ti_{1-x}V_{x}O₂ as well as the formation of metallic VO₂ or V₂O₅ particles.