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采用溶胶-凝胶法在纳米 Mg-Al 层状双氢氧化物表面包覆 SiO2纳米膜.通过酸溶分析、透射电子显微镜、FT-IP、XRD、TG 和 DSC 分析,证实了在 Mg-Al 层状双氢氧化物表面包覆了一层连续致密的、厚约 5nm 的 SiO2纳米膜.根据Al2p, Mg 2p, Si 2s 及 O1s 的电子结合能的变化,可推知在纳米 Mg-Al 层状双氢氧化物和 SiO2纳米膜表面形成了Mg-O-Si 和 Al-O-Si 键,并据此分析了形成 SiO2包覆膜的机理.经热分析表明,SiO2包覆的纳米 LDHs 和纳米 LDHs 两者在40~700℃之间失重过程大致相同,均出现了三个较为明显的质量损失阶段,至 700℃时包覆量越大的质量损失越少.纳米 LDHs 在 244.67 和 430.13℃有两个明显的吸热峰,吸热值分别达 412.28和 336.30 J/g;而包覆纳米 LDHs 只在 243.60℃处出现一个较明显的吸热峰,其吸热值为 221.25J/g.
SiO2 nanofilms were coated on the surface of nano-Mg-Al layered double hydroxides by sol-gel method.The results of acid-soluble analysis, transmission electron microscopy, FT-IP, XRD, TG, The layered double hydroxide surface is covered with a continuous dense SiO2 nanometer film with a thickness of 5nm.According to the change of the electron binding energy of Al2p, Mg2p, Si2s and O1s, Mg-O-Si and Al-O-Si bonds were formed on the surface of double hydroxide and SiO2 nanofilms, and the mechanism of forming SiO2 coating was analyzed.According to the thermal analysis, LDHs both have the same weight loss process at 40 ~ 700 ℃, there are three obvious stages of mass loss, and the greater the coating weight loss at 700 ℃, the less the LDHs at 244.67 and 430.13 ℃ Two obvious endothermic peaks, endothermic values were 412.28 and 336.30 J / g; and coated nano-LDHs only at 243.60 ℃ at a more obvious endothermic peak, the endothermic value of 221.25J / g.