2011 Volume 54 Issue 6 Pages 373-379
Mo-SBA-15 (mesoporous silica SBA-15 containing molybdenum oxides) was hydrothemally synthesized with H2MoO4, P123 as the template and tetraethylorthosilicate (TEOS). Mo species of precursor solutions and final products were characterized by Raman spectroscopy. Mo-P123 complexes are formed in solution by reaction of MoO2Cl2 dissolved in concentrated HCl and P123, but MoO2Cl2 does not react with TEOS. N2 adsorption-desorption analysis and small angle X-ray diffraction reveal that the SBA-15 framework is formed in Mo-SBA-15 synthesized. This is explained that the Mo-P123 complexes act to form the SBA-15 framework as an effective template in the hydrothermal aging. The formed molybdenum oxides are expected to be dispersed in the SBA-15 channels and their structures are affected by the volume of concentrated HCl. UV-Vis spectroscopy indicates that the tetrahedrally coordinated mono-molybdates dominate in Mo-SBA-15 when 20 mL of concentrated HCl (HCl/H2MoO4 weight ratio = 16.0) is added.
