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以草酸铌为前驱体,分别在水溶液体系、乙二醇-水的混合体系中水解制备水合氧化铌。通过XRD,TG/DSC,SEM等分析方法表征了在不同体系中所合成产物的物理化学特性,用FTIR,UV等分析方法表征了反应体系的光谱特征以及合成过程的特点。研究表明:两种体系均可合成无定型态水合氧化物,但产物特征及反应过程特征有较大区别;水溶液反应体系中,反应快速,电导率呈阶跃式变化,合成产物形貌不规则、表面粗糙、粒度均匀性差;乙二醇-水的混合反应体系中,反应易于控制,电导率变化平缓,合成产物为规则的棒状或片状、表面光滑、粒度均匀。两种反应体系得到的产物均含有吸附水、结晶水和结构水,但乙二醇-水体系产物的总含水量比水体系产物的总含水量高13.1%,并且乙二醇-水体系产物的结构水脱除起始温度点较水体系产物的结构水脱除起始温度点提高50℃左右;在700℃热处理后,二者都完全失去水份并转变为T-T相氧化铌晶体结构。反应体系光谱学特征分析表明,两种反应体系反应过程和反应产物的差别主要是由于乙二醇与草酸铌可能形成了新的更复杂的配位结构,提高了配合物中心离子的稳定性。
Niobium oxalate was used as precursor to hydrolyze niobium hydrate to prepare hydrous niobium oxide in a mixed system of aqueous solution and ethylene glycol - water, respectively. The physicochemical properties of the synthesized products were characterized by XRD, TG / DSC and SEM. The spectral characteristics of the reaction system and the characteristics of the synthesis process were characterized by FTIR and UV. The results show that amorphous system hydrate oxide can be synthesized in both systems, but the product characteristics and reaction process characteristics are quite different. In aqueous solution system, the reaction is rapid and the conductivity changes step by step. The morphology of the synthesized product is not Rules, rough surface and poor uniformity of particle size. In the mixed reaction system of ethylene glycol and water, the reaction is easy to control and the conductivity changes gently. The synthesized products are regular rods or flakes with smooth surface and uniform particle size. The products obtained from both reaction systems contained adsorbed water, crystallized water and structured water, but the total water content of the ethylene glycol-water system product was 13.1% higher than the total water content of the aqueous system product, and the product of the ethylene glycol-water system The starting temperature of structural water removal is about 50 ℃ higher than that of the water system. After heat treatment at 700 ℃, both of them lose water completely and transform into the niobium phase structure of TT phase. The spectroscopic analysis of the reaction system showed that the difference between the reaction processes and the reaction products of the two reaction systems was mainly that ethylene glycol and niobium oxalate formed a new and more complex coordination structure and increased the stability of the central ion of the complex.