Structure, Morphology, and Band Gap of Ti-V-O Mixed Oxides Processed by Coprecipitation and Calcination

Abstract

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 Ti1−xVxO2. Lattice parameters of rutile TiO2 were precisely measured to investigate vanadium substitution into single rutile phase of Ti1−xVxO2 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 Ti1−xVxO2 as well as the formation of metallic VO2 or V2O5 particles.

Electrochromic Properties of the Vanadium Pentoxide Doped with Nickel as an Ionic Storage Layer

“…It is reported [13] that chromic mixed metal oxide film has more natural colors than single chromic oxide material in their coloring states. This effectiveness is due to the improvement of the optical band gap.…”

“…The chromic mixed metal oxide films often show more natural colors than intrinsic ones in their coloring states. This is due to the improvement of the optical band gap by the metal-doping [13]. M.A.…”

“…Some techniques that were used to deposit the electrochromic oxide films are as follows: sputtering [25], evaporation [26], sol-gel [27], chemical vapor deposition [26], spray pyrolysis [28], and pulsed laser deposition [13]. Sputtering is an efficient technique for deposition of thin films.…”

Закономерности Формирования Электропроводящих Свойств Окислов Ряда Магнели

“…Если спаривание происходит вдоль одного из выделенных направлений, то при образовании π-димеров произойдет структурный ФП с сильным понижением симметрии кристаллической решетки ввиду одномерности направления спаривания [22]. Структурный ФП во всем кристалле совершается при достижении критической концентрации образовавшихся пар, после чего процесс спаривания захватывает весь объем нанокристаллита ввиду коллективного характера волновых функций, описывающих поведение в периодическом поле решетки как невзаимодействущих, так и сильно коррелированных электронов [23].…”

Patterns of formation of electrically conductive properties of oxides of the Magneli series

“…If pairing takes place along one of dedicated directions, then in the course of π-dimers formation a structural PT takes place with a strong lowering of the crystal lattice symmetry due to the one-dimensional nature of the pairing direction [22]. The structural PT in the whole crystal takes place upon achievement of the critical concentration of formed pairs, after which the process of pairing is expanded onto the entire volume of the nanocrystallite due to the collective character of wave functions that describe the behavior of both non-interacting and strongly correlated electrons in the periodic field of the lattice [23].…”