氨基多羧酸配合物前驱体的热分解行为研究

摘要

La2NiO4+δ powder was prepared by a polyaminocarboxylate complex method.XRD,TG-DTA,IR and FESEM were employed to investigate the thermal decomposition of the precursor.The results indicate that the precursor has an amorphous nature,with the coordination of DTPA and metal cations forming a bi-dentate complex.With the temperature increasing,the complex precursor first decomposed into a mixture of NiO and intermediate (LaO)2CO3,and then transformed into La2O3 at the temperatures above 600℃.Further increasing the temperature to 700℃ yielded La2NiO4+δ phase with small amounts of intermediate phases (LaNiO3 and La2O3).Homogeneous and fine powder (～100nm) with pure K2NiF4 phase could be produced by calcining the complex precursor at 900℃.%采用氨基多羧酸配合物法合成La2NiO4+δ粉体,利用XRD、TG-DTA、IR、FESEM等测试方法对合成产物进行表征,并探讨氨基多羧酸配合物前驱体的热分解行为.研究结果表明,氨基多羧酸配合物前驱体为非晶态结构,前驱体中DTPA与金属阳离子形成双齿配位结构.配合物前驱体热分解后先形成中间产物(LaO)2CO3和NiO,进一步加热中间产物(LaO)2CO3即分解为La2O3.当热处理温度达到700℃时,合成产物中形成了K2NiF4结构的La2NiO4+δ,但同时还存在少量杂相；经900℃热处理后合成产物形成单—K2NiF4相的La2NiO4+δ,合成粉料的颗粒细小、均匀(～100nm).