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

Abstract

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).