Liquid Phase Controlled Synthesis Of Tungsten Oxide, Tungstate Nanomaterials

Tungsten compound is a kind of functional materials with great importance. It has been used in the field of photocatalysis, electrochromic, optochromic, gas seniors et al. Due to their wide foregrounds of development and the anticipative market potentials, more and more attentions have been focused on the development of high-quality tungstate compound materials at large-scale among the world-wide researchers in this field.Solution and non-solution routes are two important ways to prepare nanomaterials. But non-solution route always relates to tedious procedures and high temperature, so such method needs rigid equipment and restricts its application. Solution route is popularly accepted in preparing nanomaterials for its low-cost, manageable, mild reaction conditions.Chemical reductive method is controllable. The prepared nanoparticles in sphericity are well-dispersed. Experiment results prove that hollow sphere nanoparticles could be abtained by this method. While in the hydrothermal/solvothermal process, the final particles are usually formed through a dissolution-crystal process, and the as-prepared products possess many excellences such as well-crystalline, narrow size distribution, avoid introducing impurity, forming bugs and the growth of crystal. Owing to the superiority of hydrothermal/solvothermal process, these methods are sure to meet with the requirements for preparation high-quality tungstate nanoparticles. In this dissertation, novel solution routes have been developed to prepare tungsten trioxide and tungstate nanomaterials with all kinds of morphologies using low-cost, facile sodium tungstate as raw material. And reaction conditions that have important effects on the final products have also been discussed in details. In addition, we discussed the growth mechanism of products. The main points are summarized as follows:1. A facile method has been demonstrated for the preparation of WO3 hollow nanospheres by calcining the hollow tungstate precursor at elevated temperature without destroying the morphology. In a typical procedure, the hollow precursor could be synthesized by a low temperature reductive route in alcohol-water mixed...