超声辐射沉淀法制备纳米γ -MnO2的研究
Preparation of Nanosized γ-MnO2 by Precipitation under Ultrasound Radiation
作者单位
李东升 西北大学化学系陕西省物理无机化学重点实验室西安 710069
延安大学化学化工学院陕西省化学反应工程重点实验室延安 716000 
王尧宇 西北大学化学系陕西省物理无机化学重点实验室西安 710069 
刘萍 西北大学化学系陕西省物理无机化学重点实验室西安 710069 
王文亮 陕西师范大学化学与材料科学学院西安 710062 
史启祯 西北大学化学系陕西省物理无机化学重点实验室西安 710069 
摘要: 以KMnO4和MnSO4·H2O为原料,采用超声辐射沉淀法制备出纳米γ-MnO2粉体,研究了反应物浓度、滴速、超声时间及超声功率等合成条件对粉体的影响,得出了最佳工艺条件。ICP、XRD和TEM分析表明, 施加超声辐射对反应体系有显著影响,超声辐射沉淀法获得了含K量极低,分布均匀,平均晶粒尺寸约10 nm的近球形γ-MnO2粉体,而未施加超声辐射的普通沉淀法却得到了棒状KMn8O16粉体。XPS与IR分析表明,两种方法所得粉体中Mn主要以+4价形式存在,而前者具有较多的氧缺位,由于K+进入了确定的晶格位置使后者的Mn-O键红外吸收峰明显不同于前者。
关键词: 纳米γ-MnO2  超声辐射  沉淀法  隐钾锰矿
基金项目: 
Abstract: Using KMnO4 and MnSO4 as raw materials, nanosized γ-MnO2 was prepared by a new precipitation method under ultrasonic radiation. The Effects of reaction concentration, titration rate, ultrasonic time and power on the formed nanometer γ-MnO2 were also discussed and the optimum conditions were obtained. The ICP, XRD, and TEM resuts reveal that ultrasonic radiation have a great impact on the reaction system, and it was found that the γ-MnO2 powder synthesized under ultrasonic radiation had an average diameter of 10 nm with a sphere-shape and good dispersity, and the precipitation product obtained from normal oxidation-reduction reaction was bar-shaped KMn8O16 and the average sizes were ca. 250 nm × 25 nm. The XPS and FTIR show that the Mn element, existing in two kinds of powders, is in +4 oxidation state, but the powder synthesized under ultrasonic radiation has more surface crystal oxygen vacancies. The K+ in lattice of KMn8O16 is responsible for obvious difference of their infrared absorption of Mn-O band.
Keywords: nanometer γ-MnO2  ultrasonic radiation  precipitation method  cryptomelane
投稿时间:2004-08-10 修订日期:2004-11-29
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李东升,王尧宇,刘萍,王文亮,史启祯.超声辐射沉淀法制备纳米γ -MnO2的研究[J].无机化学学报,2005,21(2):202-206.
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