Nano tungsten trioxide may be applied for producing thermal insulation master batch due to its photochromic properties. The phase structure of the nano grain size tungsten trioxide plays an important role in its photochromic properties. Therefore, the phase structure of the WO3 needs to be analyzed, and the composition of the WO3 nanocrystals must also be analyzed.
In order to further determine the composition of WO3, WO3 nanocrystals prepared by adding 0.125M Na2SO4 additive were selected for EDS characterization. The results are shown in the picture below.
The picture shows that this kind of powder is mainly composed of three elements --- W, O and Na. From the EDS data, W/O atomic ratio is about 1:3, indicating that the experimental operation is correct. The picture also shows a characteristic peak of Na element, indicating that the surface of WO3 nanowires synthesized by hydrothermal method is rich in Na element. Compared with the results of XRD and SEM, it can be found that the hexagonal WO3 nanowire of cluster structure can be formed when 0.125M Na2SO4 is used as an additive. While there are hexagonal and trigonal pores in the hexagonal WO3, and Na+ may easily enter the pore channel. In the WO3 producing process, it is of great significance to stabilize the hexagonal phase structure.
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