Abstract
The first section of this thesis is preparation of supported Brij56- or P123-SiO2 composite mesoporous silica thin films with thickness ~ 200 nm, which were dip-coated on Si-wafer, glass or Au/Cr/Si substrates. The template of mesoporous silica films were removed by supercritical fluid extraction (MeOH/SCF-CO2) at 60 oC, UV-O3 at 25 oC or thermal calcination at 400-500 oC. The SCF-CO2 modified with MeOH has been employed to remove template almost completely from Brij-56 and P123-SiO2 composite films on Si-wafer. SCF results the mesoporous silica film of higher degree of ordering and larger size of mesoporous with single mesophase than calcination. Furthermore, the supported P123-SiO2 composite films of high porosity with large surface area and pore volume, low average density and thickness were produced through UV-O3 treatment as characterized by X-ray reflectivity (XRR) and Kr adsorption, and with low refractive index of 1.32.In the second section, we report the preparation of surfactant-stabilized (22.0, 14.6 and 11.6 nm Pd/CTAB) and surfactant/mesoporous silica composites (5.0 Pd/CTAB/M48 and 3.5 nm Pd/CTAB/M41) Pd nanoparticles by using colloid and one-pot synthesis method. After that, we study the thermal-stability of Pd nanoparticles by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. In addition, the hydrogen adsorption/desorption properties of Pd nanoparticles and membrane were discussed by using in-suit XRD and X-ray absorption spectroscopy (XAS) during the hydrogen unloading or loading condition.