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 α-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.