摘要
为了研制高级氧化水处理中所需的高效稳定催化剂,采用了一种节能环保、工艺简单、无需模板的界面合成法,在H2O/CH2Cl2界面上制备出了介孔MnO2,并探究了其热稳定性.应用X射线衍射仪、傅里叶红外光谱仪、扫描电子显微镜、透射电子显微镜、比表面积及孔隙度分析仪对制备的样品进行组分和形貌的分析.结果表明:制备的介孔MnO2是由γ-MnO2和ε-MnO2组成,它是由中空的亚微米级的MnO2刺球堆积排列而成,平均孔径约为5.9 nm,比表面积为322.5 m2/g,孔容为0.451 cm3/g.在热稳定性方面,这种介孔MnO2经过400 C以下的煅烧,物相没有变化,只有晶型转变,仍保持刺球形貌;经过500 C煅烧后,MnO2变成了纯相Mn2O3,中空刺球结构发生坍塌.此外,对这种独特的介孔MnO2超结构的生长机理进行了初步的探讨.可见,界面合成法可以制备出高比表面积的形貌奇特、结构稳定的介孔MnO2.
Mesoporous manganese dioxide （MnO2） has been synthesized successfully by means of a facile and environmental friendly method by virtue of a soft interface between CH2Cl2 and H2O without templates. It＇s thermostability has also been investigated. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy analysis, scanning electron microscopy, transmission electron microscopy and an automatic surface area or pore size analyzer were applied to investigate the composition and microstructure of the as-synthesized MnO2. As a result, the as-prepared MnO2 was proven to be a mixture of ε-MnO2 and γ-MnO2 using X-ray diffraction techniques. The structure characterizations indicated a unique mesoporous structure of as-prepared MnO2 composed of hollow MnO2 sub-microspheres with thorns at surface. Nitrogen sorption analyses show that the as-synthesized MnO2 has an adsorption average pore diameter of 5.9 nm, mesoporous volume of 0.451 cm3·g-1, and Brunauer Emmett Teller specific surface area of 322.5 m2/g. The as-synthesized MnO2 which has undergone the heat treatment of temperature lower than 400 ℃, appears crystal change without change of composition. It would keep the microstructure of hollow MnO2 sub-microspheres. Howerver, heat treatment of 500 ℃ can turn the MnO2 to pure Mn2O3 along with it＇s microstructure＇s collapse. Otherwise, the possible growth mechanism of mesoporous MnO2 has been proposed. In brief, high surface area Mesoporous MnO2 with a novel and stable superstructure has been obtained by the facile interfacial method.
出处
《上海大学学报（自然科学版）》
CAS
CSCD
北大核心
2013年第4期405-410,共6页
Journal of Shanghai University:Natural Science Edition
基金
国家自然科学基金资助项目(11074161)
上海市科委基金资助项目(10JC1405400)
上海市重点学科建设资助项目(S30109)
