【摘要】 采用低过饱和共沉淀法合成了n(Co或Mg)∶n(Fe) =2∶1,3∶1,4∶1的钴铁和镁铁水滑石。XRD分析表明两者晶体结构相似 ,但TG DTA分析表明两者热稳定性存在显著差异 ,钴铁水滑石只在 180℃附近有一个吸热峰 ,而镁铁水滑石在 2 0 0℃和 36 5℃附近有两个吸热峰 ,分别对应于层间水和层板羟基及层间碳酸根离子的脱除 ,这说明后者的层间水分子和碳酸根离子与层板上的羟基及金属原子之间的相互作用力强于前者 ,镁铁水滑石的热稳定性强于钴铁水滑石更多还原

【Abstract】 CoFe and MgFe hydrotalcite(CoFe-HT, MgFe-HT) with Co/Fe and Mg/Fe molar ratios from 2 to 4 are synthesized by coprecipitation. The structures of both have been studied by means of XRD, TG-DTA and IR. Although both have the same crystal structures, their thermal stabilities are quite different. During the thermal decomposition process, CoFe-HT decomposes in one step-desorption of interlayer water, structural water and carbon dioxide occurred at the same time at 180℃, MgFe-HT exhibits two steps-desorption of interlayer water occurs at 200℃, followed by dehydroxylation of the brucite-like layers and loss of carbonate at 365℃. The results of a theoretical study indicate that the bond strengths of HO-CO 3-OH and HO-H 2O-CO 3-OH in MgFe-HT are stronger than those in CoFe-HT. It has been shown that the thermal stability of MgFe-HT is more than that of CoFe-HT.更多还原