Preparation And Photocatalytic Activity Of Nanostructural Zro₂ Based Microshperes

Nano-semiconductor photocatalytic technique has been widely used in treatment of environment pollutants and the water. As a photocatalyst, Zirconia is a metal oxide semiconductor with both oxidation and reduction properties, as well as acidity and basicity in its various structures. ZrO₂ is given nano size, special morphological and porous, it also has several advantages, for example, a larger specific surface area, rich surface oxygen vacancy and strong ion exchange ability. So, ZrO₂ has potential application value in the photocatalysis field.In this paper, based on the disadvantages of ZrO₂ that require a higher UV light when set off chemical reactions and the low photocatalytic activity, we reported a novel and simple method for preparing nanostructural ZrO₂ microspheres, and doping TiO₂ to ZrO₂ in two ways. We hope to improve photocatalytic activity of ZrO₂ by fabrication of nano/micron materials and compositing of semiconductor to reduce the optical band gap of ZrO₂. The main contents are as follows:Firstly, the concept, the reaction mechanisms, the way that improve photocatalytic capability of semiconductors and the applications of ZrO₂ in the photocatalysis field were reviewed.Secondly, we use ZrOCl₂·8H₂O and tetrabutyl titanate as raw materials, yeast as a bio-template through the microwave ethanol-thermal route to prepare ZrO₂ and TiO₂ doped ZrO₂ hollow microshperes. Their morphology, crystal shape, energy spectrum, ultraviolet spectrum, specific surface and infrared absorption spectrum were characterized and analyzed. The formation mechanism of hollow microshperes was discussed.Thirdly, we use self-made ZrO₂ microspheres as nuclear material, TiCl₄ as titanium source through self-assembly mechanism to lead the formation core-shell ZrO₂/TiO₂. The effects of TiCl₄/HCl concentration, response time on the morphology, crystal shape and ultraviolet spectrum of products were investigated. Meanwhile, the formation mechanism was studied preliminarily. Fourthly, experiments that methyl orange was photocatalytic degraded were carried out to test the photocatalytic activity of Self-made ZrO₂ hollow microshperes, ZrO₂ microshperes and ZrO₂ based microshperes. The best experimental conditions were got. Contrasting the photocatalytic activity both TiO₂ doped ZrO₂ hollow microshperes and core-shell ZrO₂/TiO₂, analyzes the reasons why the photocatalytic activity of the two was improved.