Controllable Preparation And Property Research Of Vanadium Oxide Nanomaterials

As a kind of functional materials, vanadium oxide nanomaterials present some interesting properties and wide applications. In this work, the controlled synthesis of vanadium oxide micro-nanomaterials and hierarchical nanostructured materials through liquid-phase chemistry routes are investigated. The contents include hydro/solvothermal synthesis of one-dimensional (1D) nanostruture, hollow spheres and doped VO₂ 1D solid solution, investigating the formation mechanism of vanadium oxide micro-nanomaterials in solution, designing a novel route for the control over the morphology, size and composition of vanadium oxide micro-nanomaterials, investigating the properties and applications, which provide reference for the synthesis and property research of vanadium oxide micro-nanomaterials.1. Hydrothermal synthesis of vanadium-based 1D nanostructuresMonoclinic phase VO₂ (B) nanoribbons, vanadium(IV,V) oxide nanoribbons, V2O5·H2O and other vanadium-based 1D nanostructures were prepared in the absence of templates by hydrothermally treating a home-made vanadium precursor with mixed-oxidation states. The products were characterized by XRD, TEM and SEM techniques. The formation mechanism of VO₂ (B) nanoribbons was investigated in detail, and the potential applications of VO₂ (B) nanoribbons and V2O5 hydrate nanowires as lithium battery electrodes were also studied by electrochemical methods.2. Fabrication of vanadium oxide hierarchical hollow spheresA simple one-step template-free solvothermal method including the decomposition and reduction of vanadium (IV) acetylacetone in a single solvent of N, N-dimethylformamide (DMF) was reported to synthesize vanadium oxide hollow spheres with the shell built by V2O3 nanoparticles sized less than 10 nm for the first time. The size of hollow spheres could be 200 nm, 500 nm and 1100 nm by simply varying the dosage of vanadium source. In the template-free synthesis, the presence of trace water played an important role in the production of the hollow structure. Different sized V2O5 hollow spheres were produced by calcinating corresponding V2O3 hollow spheres. The electrochemical properties of VOx hollow spheres were studied using cyclic voltammetry.3. Preparation and property of W-doped VO₂ 1D solid solutionA method combining hydrothermal process and calcinating treatment was developed to synthesize VO₂ 1D solid solution doped by tungsten with different content. XRD patterns showed that tungsten element has entered the crystal lattice of VO₂ and formed a solid solution phase, and with increasing content of doped tungsten in the samples, the structure of the product gradually transferred from monoclinic to rutile phase, which indicated that the doping of tungsten effectively decreased the clinic phase change temperature of VO₂. The optical properties of the solid solution were investigated by FTIR techniques. The results indicated that the transmittance decreased when the temperature was higher than clinic temperature of VO₂.