Study On The Synthetic Mechanism And Morphology Control Of High Performance TiO₂Assisted By Citrates Sodium

Since its commercial production in the early twentieth century, titanium dioxide （TiO₂）has been widely used as a pigment and applied in sunscreens, paints, ointments, toothpaste,etc. New physical and chemical properties emerge when the size of the material becomessmaller and smaller, and down to the nanometer scale. Properties also vary as the shapes ofthe shrinking nano-materials change. Among the unique properties of nano-materials, themovement of electrons and holes in TiO₂nano-materials is primarily governed by thewell-known quantum confinement, and the transport properties related to phonons andphotons are largely affected by the size and geometry of the materials. The specific surfacearea and surface-to-volume ratio increase dramatically as the size of a material decreases.The high surface area brought about by small particle size is beneficial to many TiO₂-baseddevices, as it facilitates reaction/interaction between the devices and the interacting media,which mainly occurs on the surface or at the interface and strongly depends on the surfacearea of the material.In this article, we synthesized high performance TiO₂nano-materials assisted bysodium citrate, characterized the products by UV-vis, FTIR, NMR, DLS, TEM, SEM andXRD, analyzed the hydrolysis and condensation process, nucleation and crystallization,and crystal growth mechanism, studied the impacts of sodium citrate on the TiO₂nano-materials. Our major work is the following:1) Effects of sodium citrate on TiCl4sol. In the sol, sodium citrate can involve in thehydrolysis reaction and combine with titanium ion to generate stable complexes. Theamounts of sodium citrate can affect the forms of the complexes. The combination ofsodium citrate and titanium ion can directly affect the condensation process andcrystallization, and induce the sol to form anatase TiO₂crystal.2) Effects of sodium citrate on TiO₂morphology and crystalline phase. The amounts ofsodium citrate can affect the particles sizes and crystalline phase directly, which bothcan be controlled by sodium citrate. Cl-and F-can also assist sodium citrate to control TiO₂morphology and crystalline phase.3) Effects of sodium citrate on TiO₂photo-degradation performance. A mixture crystal ofanatase TiO₂and rutile TiO₂can be obtained by adding a little sodium citrate into TiO₂,which can promote the degradation performance. Excess sodium citrate can reduce thequantity of the defects and electronic-hole couples of TiO₂crystal, which lower thedegradation performance. The TiO₂product can dissolve well in water, degrade manyindustrial dyes, and prepare self-cleaning glass, which can be used in our daily life.