Magnesia-incorporated mesoporous alumina with crystalline frameworks: A solid strong base derived from direct synthesis

By use of a surfactant templating method, the direct synthesis of magnesia-incorporated mesoporous alumina (mMgAl-γ) was realized via self-assembly of inexpensive inorganic salts. The structural and basic properties of the obtained materials were well characterized by various approaches. The results show that mMgAl-γ samples possess strong basicity with excellent water-resistant ability, well-defined mesoporous structure, and γ-Al₂O₃ crystalline frameworks. In comparison with wet impregnation that leads to structural damage, the direct synthesis strategy allows the mesoporous alumina to maintain good mesostructure. For example, the Brunauer-Emmett-Teller surface area of sample mMgAl(0.1)-γ can reach 328 m²·g^-1, which is obviously higher than that of the sample prepared by a conventional impregnation method (239 m²· g^-1). Further investigations evidence that the fabrication of suitable preassembled mesoporous precursors is crucial for the efficiency of the present direct synthesis strategy. In the process of calcination, the strongly basic species MgO was produced simultaneously and in situ coated on newly formed mesoporous γ-Al₂O₃ from preassembled precursors. Besides mMgAl-γ, mesoporous γ-Al₂O₃ materials functionalized with iron, chromium, and lead oxides were also successfully prepared, which demonstrates the generality of the strategy.