Synthesis, characterization and catalytic applications of mesoporous γ-alumina from boehmite sol
Synthesis, characterization and catalytic applications of mesoporous γ-alumina from boehmite sol
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DOI：
10.1016/j.micromeso.2007.08.007
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发表时间：
2008-04
影响因子：
5.2
通讯作者：
Qianyuan Liu;Aiqin Wang;Xuehai Wang;P. Gao;Xiaodong Wang;Tao Zhang
中科院分区：
文献类型：
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作者：
Qianyuan Liu;Aiqin Wang;Xuehai Wang;P. Gao;Xiaodong Wang;Tao Zhang
在这项研究中，勃姆石溶胶被用来作为铝前体制备介孔氧化铝（MA）在非离子表面活性剂作为结构导向剂的存在下，具有结晶骨架壁。氮气物理吸附实验表明，以这种方式制备的氧化铝显示出非常丰富的孔隙度与大的介孔，孔体积和孔径随着表面活性剂浓度的增加。样品中织构参数的改善应归因于三维互连的支架状通道，该通道是由刚性勃姆石纳米颗粒在表面活性剂的帮助下随机有序堆叠和凝聚而形成的。TEM观察表明，前驱体形态对介孔氧化铝的织构性质有重要影响。具有波纹状片晶形貌的样品表现出463 m2/g的大表面积，在1200°C煅烧后其减小至81 m2/g，表明强的抗烧结性。这种材料具有改善的织构性质、结晶骨架壁和高热稳定性，当用作催化剂载体时，不仅可以增加活性催化物种的分散，而且可以增强反应物分子的扩散效率和传质。作为例子，我们的MA样品表现出显着的增强催化性能的SO2催化还原CO和甲烷催化燃烧的反应。
In this study, boehmite sols were used as aluminum precursors for preparing mesoporous alumina (MA) having crystalline framework walls in the presence of non-ionic surfactants as structure directing agents. Nitrogen physisorption showed that aluminas prepared in this way displayed very rich porosities with large mesopores, and both the pore volumes and the pore sizes increased with the surfactant concentration. The improved textural parameters in the samples should be attributed to the three-dimensional interconnected scaffold-like channels, which were formed by randomly ordered stacking and condensing of rigid boehmite nanoparticles with the aid of the surfactant. TEM observations revealed that the precursor morphology had an important effect on the textural properties of the mesoporous alumina. The sample with a corrugated platelet-like morphology exhibited a large surface area of 463m2/g, which was reduced to 81m2/g after calcination at 1200°C, indicating a strong resistance to sintering. This material, with its improved textural properties, crystalline framework walls and high thermal stability, not only could increase the dispersion of the active catalytic species, but also could enhance the diffusion efficiency and mass transfer of reactant molecules when employed as catalyst supports. As examples, our MA samples demonstrated a remarkable enhancement in the catalytic performances for both reactions of SO2catalytic reduction by CO and catalytic combustion of methane.