中文摘要：

以SnCl4和LaCl3为原料，采用化学共沉淀法制备混杂La的纳米SnO2，运用DSC-TG、XRD和TEM等对混杂La的SnO2纳米粉末的物相和粒度进行了分析。结果发现：（1）采用化学共沉淀法制备混杂La的SnO2粉末，焙烧温度在400-650℃时，主要成分为SnO2，750℃以上焙烧，主要成分为La2Sn2O7和SnO2。（2）La混杂是通过阻碍SnO2由非晶体向晶体转变来抑制纳米颗粒长大，一旦晶体形成，并达到一个临界尺寸值时，La元素便开始脱溶析出，并反应生成La2Sn2O7，其对纳米晶粒长大的阻碍作用消失，晶粒将迅速长大。

英文摘要：

La-doped nanosized SnO2 powders are prepared by chemical co-precipitation method using SnCl4 and LaCl3 as raw materials. The structure and granularity of nanosized SnO2 are investigated by differential scanning calorimeter and therrno-gravimetric analysis （DSC-TG）, X-ray diffraction （XRD） and transmission electron microscope （TEM）, the main conclusions can be obtained as follows：（1） the calcination temperature can influence the production. For example, when the La/Sn hydroxide powders are calcinated under 400-650℃, the production is SnO2, when it is 750℃ upwards, the major composition are La2Sn2O7 and SnO2. （2）La-doped can efficiently prevent the growing-up of nanosized SnO2 by hinder the transformation of SnO2 from non-crystal to crystal. Once the crystal is formed and the size reached a critical value, then La startes to separate from SnO2 and the reaction production is La2Sn2O7, here the function of preventing the growing-up of nanosized crystal disappeares, and the grain can growing-up quickly.