微米级棒状氧化铝团簇体的合成及表征

Synthesis and characterization of micron rod-like alumina clusters

以γ-Al2O3粉末及碳酸氢铵为原料,采用水热技术成功制备微米级棒状氧化铝团簇体,考察反应温度、反应时间、物料配比等因素对微米级棒状氧化铝团簇体形貌的影响,并应用XRD、NMR、TEM、FTIR、SEM、N2吸附-脱附、吡啶吸附-脱附等技术分析其物化性质及结构。结果表明:当γ-Al2O3粉末与碳酸氢铵质量比为1∶1.75、反应温度为140℃、反应时间为6h时,合成的微米级棒状氧化铝团簇体直径为5~15μm,该微米级棒状氧化铝团簇体由直径50~100nm、长0.5~3μm的棒状氧化铝交叉堆积而成,比表面积为300m2/g、孔容为0.67mL/g,具有双重孔分布,可几孔径分别为3.5nm和26nm,表面同时含有六配位铝离子、五配位铝离子和四配位铝离子。

Micron rod-like alumina clusters were successfully prepared from γ-Al2 O3 powder and ammonium bicarbonate by hydrothermal method. The effects of reaction temperature, reaction time and material ratio on the morphology of rod-like alumina clusters were investigated. The physicochemical properties and structures of rod-like alumina clusters were analyzed by XRD, NMR, TEM, FTIR, SEM, N2 adsorptiondesorption and pyridine adsorption-desorption techniques. The results showed that the mass ratio of γ-Al2 O3 powder to ammonium bicarbonate was 1∶1.75, the reaction temperature was 140℃, the reaction time was 6 h and the diameter of the synthesized micron grade rod-like alumina clusters was 5-15μm.The micron-grade rod-like alumina cluster was formed by cross-stacking of rod-like alumina with a diameter of 50-100 nm and a length of 0.5-3μm. The specific surface area was 300 m2/g and pore volume was 0.67 mL/g with dual pore distribution. The pore sizes were 3.5 nm and 26 nm, respectively. It also contained six coordination aluminum ions, five coordination aluminum ions and four coordination aluminum ions.