Title: Synthesis of Ti-MCM-41 from amorphous SiO2-TiO2 xerogels
Abstract: A novel method has been developed for the synthesis of Ti-MCM-41 based on the preparation in a first step of an amorphous SiO2-TiO2 xerogel, followed by addition of a cationic surfactant and hydrothermal treatment. Ammonium hydroxide (NH3) and tetrapropylammonium hydroxide (TPAOH) solutions were used as basic agents during both the preparation of the xerogel and its subsequent hydrothermal transformation. The properties of the samples thus obtained strongly depend on the method used to prepare the raw xerogel. When employing NH3 the materials produced present a lack of mesostructure, showing that this basic agent is not suitable for promoting the xerogel reorganization around the surfactant micelles. In contrast, the use of TPAOH leads to Ti-MCM-41 samples with a high degree of mesoscopic ordering and presenting all the Ti atoms incorporated into the walls. This novel method allows Ti atoms to be first stabilized in isolated positions of a silica matrix, which avoids the formation of non-desired TiO2 phases, while the Ti content of the final Ti-MCM-41 is similar to that of the raw xerogel.
Publication Year: 2005
Publication Date: 2005-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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