天然闪锌矿原位高温X射线衍射研究

An In-situ High Temperature XRD Study on Natural Sphalerite

对天然闪锌矿进行了原位高温X射线衍射实验研究,结果表明:闪锌矿受热膨胀,27～675℃温度范围内其膨胀系数为25.61×10-6℃-1;随着温度的升高,在543℃时产生中间物相Zn3O(SO4)2,并分解产生红锌矿ZnO;在797℃时中间物相完全消失,同时出现尖晶石结构的ZnFe2O4;加热至1160℃时的产物为ZnO和ZnFe2O4。实验表明,天然闪锌矿的热改性可产生一定比例的红锌矿(ZnO),其与闪锌矿一起形成二元复合半导体。在光的激发下,该半导体体系产生的光生载流子由一种半导体注入另一种半导体,降低了光生电子-空穴对的复合几率,提高其光催化活性。本文的研究可为热改性提高天然闪锌矿光催化活性提供理论依据。

In-situ high temperature X-ray diffraction study was carried out on the natural sphalerite.The results showed that sphalerite expanded with the increasing temperature and its volume thermal expansion coefficient was 25.61×10-6 ℃-1 in the range of 27-675 ℃.During the heating,an intermediate phase Zn3O（SO4）2 was observed at 543℃,then decomposed into zincite ZnO.The complete breakdown of Zn3O（SO4）2 happened at 797 ℃,accompanied by the formation of ZnFe2O4 which had a spinel structure.At 1160 ℃,ZnO coexisted with ZnFe2O4.The experiment revealed that heat treatment of natural sphalerite could lead to the formation of a certain proportion zincite（ZnO）,which could compose a binary compound semiconductor together with sphalerite.When the compound semiconductor system was excited by certain light source,the photo-induced carrier would transfer from one semiconductor particle to the other,reducing the combination of photo-induced electron-hole pairs,which could improve the photocatalytic activity of the system.This work could be theoretically helpful in the field of enhancing the photocatalytic abilities of natural sphalerite using heat treatment.