Designing ordered mesoporous aluminosilicates under acidic conditions via an intrinsic hydrolysis method.

Acid-mediated synthesis of ordered mesoporous aluminosilicates (OMAS) with medium-to-strong Brønsted acid sites and trivalent aluminium exclusively in a tetrahedral framework structure is realized by a newly devised intrinsic hydrolysis method. In this way, we have synthesized a series of well-ordered OMAS, e.g.

Acid-Mediated Synthesis of Ordered Mesoporous Aluminosilicates: The Challenge and the Promise.

A new intrinsic hydrolysis method was employed, for the first-time, to synthesize well-ordered H-AlSBA-15 with trivalent aluminium exclusively in the tetrahedral framework structure of SBA-15. Unlike other methods, which involve incorporation of aluminium ions in both the framework (Brønsted) and non-framework (Lewis) sites of the silicate matrix, the intrinsic hydrolysis method isomorphously substitutes aluminium ions in the tetrahedral network even at high aluminium content. This unique approach relies mainly on the hydrolysis rates of the inorganic (silicon and aluminium) precursors used for the preparation in such a way that the condensation occurs simultaneously so as to overcome the usually encountered difficulties in stabilizing aluminium ions in the silicate matrix.