Kinetics of nanocrystalline MgO growth by the sol–gel combustion method
Kinetics of nanocrystalline MgO growth by the sol–gel combustion method
复制标题
DOI：
10.1016/j.micromeso.2013.10.021
复制
发表时间：
2014-02
影响因子：
5.2
通讯作者：
Alexandre R. Bueno;Renata F.M. Oman;Paula M. Jardim;Nicolás A. Rey;R. D. de Avillez
中科院分区：
文献类型：
--
作者：
Alexandre R. Bueno;Renata F.M. Oman;Paula M. Jardim;Nicolás A. Rey;R. D. de Avillez
以聚乙烯醇（PVA）和硝酸金属为前驱体，采用溶胶-凝胶燃烧法制备了纳米氧化镁。采用红外吸收光谱（IR）、x射线衍射（XRD）、BET （brunauer - emmet - teller）、透射电子显微镜（TEM）和扫描电子显微镜（SEM）对所得粉体进行了表征。研究了热处理参数对晶粒生长动力学、晶粒尺寸和比表面积的影响。MgO晶粒尺寸随温度升高而增大，比表面积随温度升高而减小。晶体生长的活化能约为223.7 kJ/mol。通过控制工艺参数，可制得晶粒尺寸为13.6 ~ 98.7 nm，比表面积为81.54 m2 g-1的氧化镁。燃烧过程中晶粒尺寸的增长与晶粒旋转聚结一致，这似乎与在较高燃烧温度下处理的样品中化学吸附水产生的外部羟基的损失有关。
Nanocrystalline MgO was synthesized via the sol–gel combustion method using polyvinyl alcohol (PVA) and metal nitrate as precursor. The obtained powders were characterized using infrared absorption spectroscopy (IR), X-ray diffraction (XRD), BET (Brunauer–Emmett–Teller), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The effects of the thermal treatment parameters on the crystallite growth kinetics, crystalline size and specific surface area were investigated. The crystallite size of MgO increases with increasing temperature, whereas the specific surface area decreases with increasing temperature. The activation energy for the crystallite growth was estimated to be approximately 223.7 kJ/mol. MgO with crystallite size in range of 13.6 nm to 98.7 nm and a specific surface area up to 81.54 m 2 g-1 can be produced by controlling the processing parameters. The crystallite size growth during combustion is consistent with grain rotation coalescence, which seems to be related to the loss of external hydroxyl groups, derived from chemisorbed water, in the samples treated at higher combustion temperatures.