pH值对溶胶凝胶-燃烧合成纳米晶LaMnO_3粉末的影响

The effect of pH value on sol-gel combustion synthesis of nanocrystalline LaMnO_3 powders

以硝酸镧、硝酸锰和柠檬酸为原料,采用溶胶凝胶燃烧合成技术制备了超细LaMnO3粉末。借助XRD、DTA、SEM、FT-IR等分析仪器研究了溶胶凝胶-燃烧合成技术合成超细LaMnO3粉末的过程,着重讨论了前驱体溶液不同pH值对溶胶凝胶燃烧合成过程及合成产物的影响。结果发现,采用溶胶凝胶燃烧合成技术能合成纳米晶的LaMnO3粉末,随前驱体溶液pH值增加,燃烧反应速率增加,合成粉体的平均晶粒尺寸随pH值增加而减小。通过控制前驱体溶液pH值能一步合成超细LaMnO3颗粒(粒径<200nm)。

Nanocrystalline LaMnO3 powder was synthesized by sol-gel combustion synthesis.The influence of pH value of the precursor solution on the combustion behavior and as-synthesized powder were investigated with the help of thermal analysis,infrared spectra,X-ray diffraction technique and scanning electron microscopy.The results showed that nanocrystalline LaMnO3 powders can be synthesized by sol-gel combustion technique.The combustion rate increased with the pH value increasing.The crystallite size of the as-formed LaMnO3 powder decreases with pH value increasing.LaMnO3 powders with particle size less than 200nm can be obtained by control the pH value.