Synthesis, characterization of monodispersed MgO microspheres and thermal decomposition kinetics of its precusor
来源期刊：中南大学学报(英文版)2014年第9期
论文作者：YUAN Pei(袁培) GUO Ya-kun(郭雅坤) GU Kun-hong(谷昆泓) XIAO Qi(肖奇)
文章页码：3463 - 3469
Key words：PEG-400; monodisphersed MgO; thermal decomposition kinetics; isothermal prediction
Abstract: Monodispersed MgO microspheres were successfully synthesized by a simple solvothermal method using PEG-400 as solvent. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results reveal that the precusor was monoclinic Mg5(CO3)4(OH)2·4H2O and composed of nanosheets with the thickness of about 250 nm. By calcining the precusor at 500 °C for 5 min, cubic MgO with similar morphology was obtained. According to the SEM images, it is found that the volume ratio of PEG-400 to deionized water is considered as a crucial factor in the evolution of the morphology. Based on the SEM images obtained under different experimental conditions, a possible growth mechanism which involves self-assembly process was proposed. The thermal decomposition process of MgO precusor was studied by thermogravimetry-differential thermogravimetry (TG-DTG) at different heating rates in air. Thermal analysis kinetics results show that the most probale mechanism models of MgO precusor are An and D3, respectively. In addition, isothermal prediction was studied to quantitatively characterize the thermal decomposition process.
YUAN Pei(袁培), GUO Ya-kun(郭雅坤), GU Kun-hong(谷昆泓), XIAO Qi(肖奇)
(School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China)
Abstract:Monodispersed MgO microspheres were successfully synthesized by a simple solvothermal method using PEG-400 as solvent. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results reveal that the precusor was monoclinic Mg5(CO3)4(OH)2·4H2O and composed of nanosheets with the thickness of about 250 nm. By calcining the precusor at 500 °C for 5 min, cubic MgO with similar morphology was obtained. According to the SEM images, it is found that the volume ratio of PEG-400 to deionized water is considered as a crucial factor in the evolution of the morphology. Based on the SEM images obtained under different experimental conditions, a possible growth mechanism which involves self-assembly process was proposed. The thermal decomposition process of MgO precusor was studied by thermogravimetry-differential thermogravimetry (TG-DTG) at different heating rates in air. Thermal analysis kinetics results show that the most probale mechanism models of MgO precusor are An and D3, respectively. In addition, isothermal prediction was studied to quantitatively characterize the thermal decomposition process.
Key words:PEG-400; monodisphersed MgO; thermal decomposition kinetics; isothermal prediction
