TiCl_4高温气相氧化合成纳米二氧化钛颗粒的研究Ⅱ.颗粒晶型结构控制

Study on the Nanosized TiO_2 Particles Synthesized by T iCl_4 High Temperature Gas Phase Oxidation Ⅱ. Crystal Structure Contro lling

在高温气相反应器中,利用TiCl4氧化反应制备纳米TiO2颗粒,分析了TiO2颗粒化学组成,研究了操作参数对TiO2晶型结构的影响。结果表明,TiO2颗粒中金红石相含量随反应温度变化出现最大值,并随停留时间延长而增大;加入AlCl3能增加TiO2表面的氧空位,促使锐钛相向金红石相转化,使金红石相含量较未掺铝时大幅度提高,当反应温度1100℃、进料中AlCl3和TiCl4摩尔比为0.25、停留时间为1.73s时,可得到纯金红石相纳米TiO2颗粒。

Nanosized titania particles were synthesized by the gas-phase oxidation of titanium tetrachloride in a high tempe rature tubular aerosol flow reactor. The chemical composition of the t itania particles was analyzed, and the effect of processing parameters on the particle crystal structure was studied. The results showed that the rutile weight fraction increased with increasing residence time, and reached a maximum value between 1200～1300℃. The addition of AlCl 3 can enhance the rutile fraction.The effect of aluminum on the pha se transformation was attributed to the formation of excess oxygen vaca ncies as Al2O3 and TiO2 form a substitution solid solution. Pure rutile of titania particles was formed at T=1100℃,Xinlet =0.25 and t=1.73s.