水热合成VO_(2)粒子的微观形貌调控及其热致相变性能

Morphology control of VO_(2) particles synthesized by hydrothermal method and its thermally induced phase transition properties

采用水热法合成了VO_(2)纳米粒子,利用XRD、DTA、SEM和DSC等手段对VO_(2)粒子的晶体结构、微观形貌、热演变过程及其热致相变性能进行了表征,探讨了乙醇和椰果添加量对VO_(2)微观形貌及热致相变性能的影响规律。结果表明,水热法合成的VO_(2)粒子均为VO_(2)(B)晶体结构,经680℃热处理后晶体结构由B相VO_(2)(B)转变为M相VO_(2)(M);乙醇和椰果的加入,会在一定程度上引起结晶度和晶粒尺寸的减小,并且有“线球”状颗粒出现;反应液中添加椰果和50%乙醇合成的VO_(2)样品相变焓为41.41 J/g,具有最佳的热致相变性能。

VO_(2) nanoparticles were synthesized by hydrothermal method.The crystal structure,microscopic morphology,thermal evolution process and thermally induced phase transition properties of VO_(2) were characterized by XRD,DTA,SEM and DSC.The influence of ethanol and coconut addition amount in the reaction solution on the microscopic morphology and thermally induced phase transition properties of VO_(2) was discussed.The results showed that the VO_(2) particles synthesized by the hydrothermal method all exhibited VO_(2)(B)crystal structure,and the crystal structure changed from B phase VO_(2)(B)to M phase VO_(2)(M)after heat treatment at 680℃.The addition of ethanol and coconut could cause the decrease of crystallinity and grain size to some extent,and some“thread ball”particles appeared.The phase transition enthalpy of the VO_(2) sample synthesized by adding coconut fruit and 50%ethanol to the reaction solution was 41.41 J/g,and the as-prepared VO_(2) particles exhibited the best thermally induced phase transition performance.