熔盐法合成钨酸锌纳米晶及花朵状氧化锌

Molten Salt Synthesis of Zinc Tungstate Nanocrystals and Flower Like Zinc Oxide

采用熔盐法成功制备出了钨酸锌（ZnWO4）纳米晶。用XRD、SEM分别对产物的相组成、粒度、显微结构等进行了表征。结果表明：以Na2WO4·2H2O、Zn（NO3）2·6H2O为原料,NaNO3-LiNO3为熔盐,分别在200-400℃保温12 h均能合成纯相的ZnWO4粉体;当温度达到500℃时生成花朵状的ZnO片状粉体;ZnWO4颗粒的形貌与煅烧温度和保温时间有密切关系,随温度升高,颗粒形貌的演变过程为：当温度为200℃时生成纳米颗粒;升高温度至300℃时,生成棒状纳米晶体;继续升高温度到400℃时,形成了块状的微米晶体。随着保温时间的延长,颗粒形貌的演变过程为：由纳米颗粒转变为棒状纳米晶体。

Zinc tungstate （ZnWO4） nanocrystals were prepared by the molten salt method. The product composition, particle size and microstructure were characterized by XRD and SEM respectively. The results show that： pure ZnWO4 nanocrystals were synthesized at about 200-400℃ for 12 h in a NaNO3- LiNO3 salt system with Na2WQ · 2H20 and Zn（NO3） 2·6H2O as raw materials. When the temperature reaches 500 ℃, the flower like ZnO powder was formed. The morphology of ZnWQ particles is closely related to the calcination temperature and the holding time. With the increase of temperature, the evolution of the particle morphology is： When the temperature is 200℃ to generate nano particles; increase the temperature to 300℃, the formation of rod like nanocrystals; continue to increase the temperature to 400℃, the formation of a block of micro crystal. With the prolonging of the holding time, the evolution of particle morphology is changed from nano particles to rod like nanocrystals.