다양한 계면활성제를 지지체로 이용한 실리카 기반 다공성 소재 합성 및 특성평가

Abstract

Mesoporous materials have attracted much attention in various applications due to their high surface areas, ordered pore structures, easily controlled pore size and adjustable framework composition. These advantages of mesoporous materials can be applied to catalysis, adsorption, separation processes, energy-related field, nanotechnology and so on. There have been lots of researches in order to develop various kinds of potential application fields through the design of mesoporous materials with controls of pore structures, morphologies and framework compositions. Here we focus mainly on materials with framework compositions and ordered pore formations because it is believed that the mesoporous materials having uniform morphology, size, and pore characteristics can be designed by using various method such as sol-gel process and hydrothermal process. In chapter 1, we synthesized titanium-substituted mesoporous silica particles with controlled pore structures as the hydrogen storage materials. In order to optimize their properties, we performed synthetic approach to incorporate titanium into mesoporous materials by using hexahydrated titanium as a titanium source and various surfactants as templates. It could be confirmed that the framework of titanium-substituted mesoporous silica materials consists of the highly dispersed titanium oxide species having a tetrahedral coordination through various analysis. In addition, we make them suitable for applications in hydrogen storage through control of mesopore structures. In chapter 2, we studied a new approach to the synthesis of lamellar- mesostructured silica materials using double-chained surfactants as templates. The obtained materials have symmetrical lamellar-vesicular morphology, narrow distribution of pore size, large volume of pores. Since the lamellar-mesostructured silica in this chapter has enhanced morphological stability and ordered pore channels, it can be used for the preparation of the nanocomposites with polymer intercalated in lamellar-pore channel. The nanostructures and morphologies of prepared mesoporous silica materials were investigated by field-emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD) and N2 adsorption-desorption isotherms. In addition, titanium-substituted mesoporous silica materials were characterized by Energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) and photoluminescence (PL) in order to understand titanium element in silica framework.