【摘要】 以V₂O₅,HCl,N₂H₄·2HCl和NH₄HCO₃为原料合成了紫红色多晶（NH₄）₅[（VO）₆（CO₃）₄（OH）₉]·10H₂O（I）,产率80％～95％.在N₂气流中对前体I进行了TG/DTG和DTA热分析.研究了前体I在N₂-空气气流中热解时氧分压（po₂）和反应温度对产物VO₂整比性的影响。结果表明,在500℃条件下,VO_x中的x值与po₂呈正比关系,在po₂=30.3 Pa条件下,在450～520℃区间,产物为缺氧VO₂;在t<450℃和t>520℃时,产物为富氧VO₂.在合适的条件下,成功地合成了从VO_1.927到VO_2.080之间不同整比性的VO₂粉体.产物组成均匀,其XRD谱未观察到非VO₂的杂质峰.VO₂粉体颗粒的平均粒径为20nm,粒度分布均匀并呈球形。更多还原

【Abstract】 The violet polycrystalline (NH4)5 [(VO)6(CO2)4(OH)9] ·10H2O( Ⅰ ) was synthesized by using V2O5, HC1, N2H4 ?2HC1 and NH4HCO3 as the starting materials. The yield was 80 %- 95%. The TG/DTG and DTA of I were studied in a flow of N2. The effects of partial pressure of oxygen(po2) in N2-air flow and temperature of reaction on VO2 stoichiometry were investigated in the pyrolysis of Ⅰ in a silica tube. The results show that x value of VOx is proportional to po2 at pyrolysis temperature of 500 ℃ At po2 = 30. 3 Pa and in the temperature range from 450 to 520 ℃ the products are oxygen-deficient VO2, and when the temperature is lower than 450 ℃ or higher than 520 ℃ the products are oxygen-rich VO2. In this paper, various stoichiometry VO2 powders from VO1.927 to VO2.080 were successfully synthesized by pyrolysizing the precursor. XRD patterns of VO2 show that none of the impurity peaks was observed. The SEM micrograph of sample indicates that as-prepared VO2 is spherical particles with mean size 20 nm and is homogeneous in distribution. Further experiments testify that the composition of nano-powders is homogeneous.更多还原