Molybdenum oxide-organosilane hybrids through sol–gel process

Abstract

From reactions between tetraethylortosilicate (TEOS) and nitrogen containing organosilanes of general formula (C 2H 5O) 3Si–R; R=–(CH 3) 2NH 2, –(CH 3) 2NH(CH 2) 2NH 2 and –(CH 3) 2NH(CH 2) 2NH(CH 2) 2NH 2, with lamellar molybdenum trioxide (α-MoO 3), four hybrid matrices, named here as MoSil, MoN1, MoN2 and MoN3, respectively, were synthesized, through sol–gel process. The obtained matrices were characterized by elemental analysis, Infrared spectroscopy, thermogravimetry, scanning electron microscopy, X-ray diffraction patterns, surface area measurements and 29Si CPMAS NMR spectroscopy. The organic moiety contents are 1.7, 2.0 and 0.9 mmol g −1 for MoN1, MoN2 and MoN3 matrices, respectively. The measured surface areas are 0.61; 78.12; 1.85; 0.59 and 2.53 m 2 g −1 for MoO 3, MoSil, MoN1, MoN2 and MoN3 matrices, respectively. Molybdenum oxide exhibts a single mass loss step in TG curve, due to the sublimation of the oxide, starting at 730 °C.The MoSil matrix exhibits a similar TG curve profile, but the thermal degradation takes place at 704 °C. MoN1, MoN2 and MoN3 matrices shows mass loss steps of 20%, 30% and 23%, respectively, associated with the organic moiety. The 2 θ values for the 001 diffraction plane were 12.64, 13.20, 12.82, 12.84 and 12.90° for MoO 3, MoSil, MoN1, MoN2 and MoN3 matrices, respectively, indicating that the organic species are at the surface, and not inside the interlayer space.