两种方法制备的纳米水滑石晶体结构与热稳定性的比较研究

Comparative Study on Structure and Thermal Stability of Nano-Hydrotalcites Synthesized by Two Methods

分别采用共沉淀法和机械力化学/原位结晶法制备纳米水滑石,通过X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、热重-差示扫描量热分析(TG-DSC)及红外光谱(IR)等方法对比分析了两种纳米水滑石在表观形貌、晶体结构和热稳定性等方面的差异。结果表明,与共沉淀法制备的纳米水滑石相比,机械力化学/原位结晶法制备的纳米水滑石结晶度更高、晶粒呈规则的六边形片状形貌、晶粒粒径约为40 nm、粒度分布均匀,且在TG-DSC曲线上的吸热峰面积、失重量和失重速率较小,热稳定性更好。

Nano- hydrotalcites were synthesized by the coprecipitation and mechanochemistry / in-situ crystallization method,respectively. The differences in morphology,crystal structure and thermal stability were analyzed using X- ray diffraction（ XRD）,field emission scanning electron microscope（ FE- SEM）,thermogravimetry- differential scanning calorimetry（ TG- DSC）,and infrared spectroscopy（ IR）. The results showed that,compared with nano- hydrotalcites synthesized by the coprecipitation,the nano- hydrotalcites synthesized by the mechanochemistry / in- situ crystallization were more well crystallized,and had more uniform size distribution,which with regular hexagon layer shape and particle size of 40 nm. Moreover,due to the smaller aera of endothermic peak,weight loss,and mass loss rate of endothermic peaks in TG- DSC curves,nano- hydrotalcites synthesized by mechanochemistry / in- situ crystallization had better thermal stability than those synthesized by coprecipitation.