Preparation and characterization of a supported Si3N4 membrane via a non-aqueous sol–gel process

We report a novel fabrication process of a mesoporous Si₃N₄ membrane on an Al₂O₃ support via a non-aqueous sol–gel technique. The membrane was prepared by dipping an -Al₂O₃ support disk into a silicon diimide sol that was synthesized by catalytic ammonolysis of tris(dimethylamino)silylamine, H₂NSi(NMe₂)₃. The SEM image and nitrogen adsorption analysis indicate that amorphous Si₃N₄ layers with nano-sized pores have formed on the surface and also inside the pores of the Al₂O₃ support disk. The new membrane demonstrates high selective absorption of NO₂, suggesting a potential application as a selective filter for gas sensors.