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以三嵌段聚合物F127为模板剂,乙醇为溶剂,利用溶剂挥发诱导自组装法合成了Ca-Zr-P-O和Al-Zr-P-O有序介孔多金属磷酸盐分子筛。采用N_2吸附-脱附分析、扫描电子显微镜和小角X射线衍射分析了材料的介孔结构的有序性及其热稳定性;通过红外光谱、魔角核磁共振、X射线光电子能谱和紫外可见漫反射光谱研究了2种介孔分子筛骨架结构中金属离子的存在状态。结果表明:2种磷酸盐分子筛,均属于二维六方有序介孔结构,骨架结构为非晶态,平均孔径介于7~10 nm,比表面积达120~260 m~2/g。Ca~(2+)和Al~(3+)均匀分散在分子筛的孔壁骨架结构中,Ca~(2+)对[ZrO_4]配位结构影响较大,Al~(3+)具有良好的配位能力且不影响[ZrO_4]配位结构。Ca~(2+)和Al~(3+)性质上的差异导致2种介孔磷酸盐材料具有不同的热稳定性:Ca_(0.25)Zr_(0.75)PO经700℃焙烧5 h后能维持有序的介孔结构,Al_(0.5)Zr_(0.5)PO经800℃焙烧仍能保持有序介孔结构。
The mesoporous multi-metal phosphate molecular sieves Ca-Zr-P-O and Al-Zr-P-O were synthesized by the self-assembly method using the triblock polymer F127 as a template and ethanol as a solvent. N_2 adsorption-desorption analysis, scanning electron microscopy and small-angle X-ray diffraction were used to analyze the orderliness and thermal stability of the mesoporous structure. The structure of the mesoporous material was characterized by infrared spectroscopy, magic angle nuclear magnetic resonance, X-ray photoelectron spectroscopy and UV- Diffuse reflectance spectroscopy was used to investigate the existence of metal ions in the two mesoporous frameworks. The results show that the two kinds of phosphate molecular sieves belong to the two - dimensional hexagonal ordered mesoporous structure. The skeleton structure is amorphous. The average pore size is between 7 and 10 nm and the specific surface area is 120-260 m 2 / g. Ca 2+ and Al 3+ are uniformly dispersed in the pore-wall framework of the molecular sieve. Ca 2+ has a strong influence on the [ZrO 4] coordination structure, and Al 3+ has good The coordination ability does not affect the [ZrO 4] coordination structure. The difference of Ca 2+ and Al 3+ properties leads to different thermal stability of the two mesoporous phosphate materials: Ca_ (0.25) Zr_ (0.75) PO can be maintained after calcination at 700 ℃ for 5 h With the ordered mesoporous structure, the Al_ (0.5) Zr_ (0.5) PO can still maintain ordered mesoporous structure after calcination at 800 ℃.