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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 experiments on natural sphalerite show that sphalerite expands in temperature and its expansion coefficient is 25.61 × 10-6 ℃ -1 in the range of 27-675 ℃. With the increase of temperature High, producing intermediate phase Zn3O (SO4) 2 at 543 ℃ and decomposing to produce zinc oxide ZnO; intermediate phase completely disappeared at 797 ℃ and spinel ZnFe2O4 appeared at the same time; product heated to 1160 ℃ For ZnO and ZnFe2O4. Experiments show that the thermal modification of natural sphalerite produces a certain proportion of zinc oxide (ZnO), which together with sphalerite form a binary composite semiconductor. Under the excitation of light, the photo-generated carriers generated by the semiconductor system are injected into another semiconductor by one kind of semiconductor to reduce the recombination probability of photo-generated electron-hole pairs and improve the photocatalytic activity. The research in this paper can provide a theoretical basis for improving the photocatalytic activity of natural sphalerite by thermal modification.