摘要:
以硫酸氧钒为钒源,氢氧化钠为沉淀剂,采用化学沉淀法—水热晶化法制备纳米VO2粉体,研究了化学沉淀过程中钒浓度、沉淀pH、反应温度、反应时间、表面活性剂种类及用量对前驱体粒径的影响,采用X射线衍射、SEM、粒度分析及热分析等方法对产品的粒径分布、晶型、形貌及相变温度进行了分析。结果表明,在钒浓度为0.1 mol/L、沉淀pH为3.7、反应温度为20℃、反应时间为5 min、十六烷基三甲基溴化铵(CTAB)用量为0.1%时,前驱体的最小粒径为210 nm。得到的前驱体在260℃温度下于去离子水中晶化4h后,得到了均一性良好的高纯度M相VO2,平均粒径为205 nm,相变温度为65.3℃。
Abstract:
Nanopowders of VO2 were prepared by chemical precipitation assisted with hydrothermal crystallization using vanadyl sulfate as the vanadium source and sodium hydroxide as the precipitant.The influences of vanadium concentration,pH value of precipitation,reaction temperature,reaction time,type and dosage of surfactants on the particle size of precursor during chemical precipitation were studied.The crystal form,morphology,the size distribution and phase-transition temperature of products were analyzed by X-ray diffraction,SEM,particle size analysis and thermal analysis,respectively.The results show that the precursor with a minimum size of 210 nm can be obtained at the concentration of vanadium of 0.1 mol/L,the precipitation pH of 3.7,the reaction temperature of 20 ℃ for 5 min and the dosage of CTAB of 0.1%.High purity and homogeneity of M-VO2 with the average particle size of 205 nm and the phase transition temperature of 65.3 ℃ can be obtained by crystallization of the precursor at 260 ℃ for 4 h in deionized water.
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