Synthesis of Vanadium Dioxide Powder with Thermochromic Property by Hydrothermal Treatment

• Main Authors: I-Lin Ho, 何義麟
• Other Authors: Thomas C.-K. Yang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/mbackd

碩士 === 國立臺北科技大學 === 化學工程研究所 === 96 === Nowadays, energy-saving concept has been an important issue due to the blooming of environmental consciousness. Thermochromic property of vanadium dioxide (VO2) exists semiconductor phase in room temperature and transfer to metal phase when temperature increased to 68℃. Therefore, the IR transmission decreased in summer, which prevented the room temperature increased. In contrast, the IR transmission increased in winter, which created energy-saving effect. In this study, hydrothermal method was employed to prepare vanadium dioxide powder. Vanadium pentoxide powder and ethanol were well mixed with appropriate of amount distilled water. The well mixed powder solution was within ultrasound both, then transferred into a 450 ml stainless steel autoclave to carry out a hydrothermal reaction. The resulting precipitate was collected by filtering, washing, and drying at 80℃ for 3 hours. Vanadium dioxide monoclinic structure was converted to rutile structure through calcining with high temperature at inert atmosphere. SEM, XRD, FTIR and DSC were utilized to acquire the information of morphology, crystallinity, optical properties and thermochromism temperature, respectively. As estimated from SEM result, the vanadium dioxide powder size is about 200nm. Hydrothermal treatment in low temperature helped to form the vanadium dioxide (B). However, structural morphology was changed from belt shape to round gradually when hydrothermal treatment temperature increased. Crystal of vanadium dioxide (M), (B) type or V6O13 phase were coexisted when calcined in low or high temperature. Thermochromism of phase transfer temperature is between 68℃-74℃, which proved thermochromism property of vanadium dioxide.