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研究层状双金属氢氧化物(LDH)的热分解过程对以其为前体制备双金属复合氧化物可提供理论指导。采用热重差热分析研究了镁铝摩尔比分别为2、3和4的LDH的热分解行为,并对热分解过程进行了动力学研究。采用红外光谱以及X射线衍射研究了Mg2Al-LDH在不同焙烧温度热分解产物的结构特点,结果表明层间碳酸根阴离子的脱除温度范围宽,约从250℃到700℃,但主要是在330～400℃之间进行的;LDH热分解过程脱除层间阴离子和层板羟基脱水的同时,伴随新相生成,500～700℃条件下,LDH的分解过程比较完全,形成了双金属氧化物。
Studying the thermal decomposition process of layered double hydroxide (LDH) can provide theoretical guidance for preparing bimetal composite oxide as precursor. The thermogravimetric analysis was used to investigate the thermal decomposition behavior of LDH with molar ratios of Mg, Al of 2, 3, and 4, respectively. The thermal decomposition kinetics was also studied. The structural characteristics of the pyrolytic products of Mg2Al-LDH at different calcination temperatures were investigated by FTIR and X-ray diffraction. The results showed that the removal temperature of interlayer carbonate anions ranged from about 250 ℃ to 700 ℃, but mainly at 330 ~ 400 ℃; LDH thermal decomposition process to remove interlayer anions and laminates hydroxyl dehydration at the same time, with the new phase formation, 500 ~ 700 ℃ under the conditions of LDH decomposition process is relatively complete, forming a bimetallic oxide .