Controllable Synthesis And Photocatalytic Performance Of TiO₂ Nanomaterials

As a traditional photocatalyst,TiO₂ has been active in the field of semiconductor materials owing to the advantages of chemical stability,low toxicity,high activity and cheap.However,because of the small light response range and low light utilization,it is necessary to improve the photocatalytic performance through modification.The morphology of TiO₂determines its specific surface area and structural properties,and becomes a factor affecting photocatalytic performance.In this paper,a simple solvothermal method is used to modify the TiO₂ from the aspects of morphology control,crystal transformation and regulation of primary nanobuilding blocks,thereby improving its photocatalytic activity.Main research contents are shown as follows:?1?The TiO₂ hollow microspheres composed of mesoporous nanospheres,nanowires and nanoparticles are synthesized by using butyl titanate as Ti source and via solvothermal method under the action of NH₃?H₂O and NaOH.Recorded as THSs,THWs,THPs.The effects of morphology,structure and other optical and electrical properties of the three samples were analyzed by various methods.And RhB,phenol and Cr?VI?were used to study the photooxidation and reduction properties of the samples photocatalyst.The results show all of these TiO₂ hollow microspheres are considered to be hierarchical nanostructures.The as-synthesized products are similar in the macrostructure and the crystallographic structures,except the primary nanobuilding blocks.Among them,THSs can provide more active sites for the adsorption of reactants due to the higher specific surface area,which is beneficial to the transfer of substances in photocatalytic reactions,as well as high charge separation and transport efficiency,which makes them have good photocatalytic properties.The photooxidation activity of THSs is 100%,the degradation rate of phenol is 96.5%,and the photocatalytic reduction is 63.5%.The experimental results of free radical capture show that O₂^·-and h⁺are the main active species in the photocatalytic degradation of RhB.?2?The tubular anatase-type TiO₂ was prepared by hydrothermal method using butyl titanate as titanium source.The effects of NaOH addition and hydrothermal time on its structure and morphology were studied.RhB was used as a degradant to test the photocatalytic properties of the products.The results show that the optimum conditions for synthesizing anatase nanotube TiO₂ are adding 0.16 g NaOH and hydrothermal reaction for48 h.The addition of NaOH and hydrothermal time will directly affect the crystalline form,crystallinity and morphology of the product.Flake and tubular anatase type TiO₂ and flower-like and tubular titanium plate type TiO₂ appeared.The photocatalytic results show that the performance of anatase phase is higher than that of slate phase.The degradation rate of RhB by anatase nanotube TiO₂ can reach 100%after 40 min exposure to simulated sunlight,which has the best photocatalytic performance.