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采用Nb2O5、NaOH和KOH为原料通过水热法合成出树状和针状铌酸钾钠纳米晶体,对反应条件对产物形貌的影响进行了讨论。X-射线衍射结果可知在150℃时可形成纯相钙钛矿结构铌酸钾钠。通过扫描电镜图片可知,只有在KOH摩尔比占总的碱浓度的15%时才能合成出树状和针状铌酸钾钠。Nb2O5粉末和NaOH和KOH在150℃反应5d后生成宽度为50~200nm的针状铌酸钾钠晶体。以Nb2O5纳米带和NaOH和KOH为原料,在150℃反应1d可形成宽度为50~150nm的树状铌酸钾钠晶体。Nb2O5纳米带在晶体生长过程中起到模板的作用,随着反应过程碱液中KOH所占比例的增大,铌酸钾钠的形貌会从针状和树状转变成颗粒状。
The dendritic and acicular sodium potassium niobate nanocrystals were synthesized by hydrothermal method using Nb2O5, NaOH and KOH as starting materials. The effects of reaction conditions on the morphology of the products were also discussed. X-ray diffraction results show that at 150 ℃ can form pure phase perovskite potassium sodium niobate structure. Scanning electron micrographs show that dendritic and acicular sodium potassium niobate can be synthesized only when the KOH molar ratio is 15% of the total alkali concentration. After reaction of Nb2O5 powder with NaOH and KOH at 150 ℃ for 5d, auricular sodium potassium niobate crystals with a width of 50 ~ 200nm were formed. Nb2O5 nanoribbons and NaOH and KOH as raw materials, reaction at 150 ℃ 1d to form a width of 50 ~ 150nm dendritic sodium potassium niobate crystals. The Nb2O5 nanobelts play a role of template in the crystal growth. With the increase of the proportion of KOH in the solution, the morphology of potassium sodium niobate changes from acicular and dendritic to granular.