Preparation of a mesoporous silicon aluminium nitride via a non-aqueous sol–gel route

A high-surface-area silicon aluminium imide based gel Si3Al(NH)x(NH2)y(NMe2)z was prepared via catalytic ammonolysis of tris[tris(dimethylamino)silylamino](tetrahydrofuran)alane, (C4H8O)Al[HNSi(NMe2)3]3. The structure of the gel and the mechanism of formation are elucidated. Pyrolysis of the gel under NH3 flow at 1000 °C gave an amorphous Si–Al–N ceramic composite in which silicon is tetrahedrally coordinated with nitrogen and aluminium is present as mixed AlN4, AlN5 and AlN6 units. The Si–Al–N composite exhibits a mesoporous structure with high surface area (190 m2 g−1) and narrow pore size distribution (2–9 nm).