爆轰法合成超小TiO2的光催化性能分析

颗粒尺寸是影响TiO2光催化活性的重要因素,颗粒越小其光催化效率越高.在密闭的反应釜内引爆用含钛前驱体、硝酸铵、黑索金与一定量的聚苯乙烯小球制备的浆状混合炸药制备了超小的TiO2纳米颗粒.研究了炸药配比对TiO2的形貌、分散性、颗粒尺寸的影响,并通过降解甲基橙溶液表征超小TiO2的光催化性能.结果发现:制备的TiO2由金红石相与锐钛矿相组成,大部分颗粒呈球形或不规则四边形,尺寸在10nm左右,少量颗粒尺寸大于20nm,结晶度较好.炸药配比对TiO2的结晶度、颗粒大小、分散性等有较大影响.TiO2的禁带宽度在2.8eV左右,低于锐钛矿相与金红石相的禁带宽度,能够提高太阳光的利用率.爆轰制备的超小TiO2催化降解甲基橙溶液50min时,甲基橙的降解率为30;,明显高于爆轰法制备的颗粒较大的TiO2与铜粒子掺杂的纳米TiO2的光催化速率,光催化性能得到明显提高.

Photocatalytic Property Analysis of Ultra Small TiO2 Synthesied by Detonation Method

The particle size is a very important factors for photocatalytic activity of TiO 2 , and the smaller TiO2 has a higher photocatalytic property .A slurry explosive mixed by Ti-contained precursor , ammonium nitrate, hexogen and some polystyrene beads was exploded in a pressure-tight reaction kettle to prepare ultra small TiO2 nanoparticle.The influence of explosive formulation on morphology , dispersivity and particle size was studied .Furthermore, the photocatalytic property of ultra small TiO 2 was tested by degradation of methyl orange solution .It is found that the TiO2 nanoparticles are consisted of rutile and anatase;most of them are spherical or irregular quadrangular; the particle size is about 10 nm; a small amount of particles'size is greater than 20 nm.The crystallinity of TiO2 is good.The explosive formulation has great influence on crystallinity , particle size and dispersivity of TiO 2 .The band gap of TiO2 is about 2.8 eV, which is less than that of anatase and rutile , and it indicates that the ultra small TiO2 can increase the utilization of sunlight .The degradation rate of methyl orange is 30;when the ultra small TiO2 was used to degrade methyl orange solution for 50 min, which is much higher than the TiO 2 and Cu-doped nano TiO 2 prepared by detonation method with larger particle size .The photocatalytic property is improved obviously .