不同形态SnO2纳米晶的制备

In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO2 by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO2 nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCI4 as the reactant. With the initial pH of 1.8 or 1.34, we prepared uniform and well-dispersed SnO2(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen 1 prepared at pH＝1.8 showed the rod-like shape with an average size of 5 nm×20 nm, while the other one(specimen 2)prepaed at pH＝1.34 showed a granular shape with an average size of 10 nm. XRD experiments showed that specimen 1 had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO2. The experiment results indicated that the morpholgy of SnO2 nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions.

Morphologically Selective Synthesis of Nanocrystalline SnO2

In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO2 by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO2 nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCI4 as the reactant. With the initial pH of 1.8 or 1.34, we prepared uniform and well-dispersed SnO2(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen 1 prepared at pH＝1.8 showed the rod-like shape with an average size of 5 nm×20 nm, while the other one(specimen 2)prepaed at pH＝1.34 showed a granular shape with an average size of 10 nm. XRD experiments showed that specimen 1 had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO2. The experiment results indicated that the morpholgy of SnO2 nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions.