Synthesis And Understanding The Mesoporous Materials By Using The Mixed Surfactant As Template

The mesoporous materials with uniform and larger mesopores and higher surface area have been widely used in many fields such as ion-exchange, adsorption and separation, and industrial catalysts. However, compared with microporous zeolites, the mesoporous materials show poor hydrothermal, thermal, and mechanical stabilities which seriously limit their extensive uses.Notably, mesostructured materials are prepared at room temperature or relatively low temperatures (< 140°C), which is quite different from the higher temperatures (150-220°C) used for the synthesis of many microporous crystals of zeolites or phosphates. As with silica-based mesoporous materials, because surfactant molecules will not be able to direct mesoporous structure formation due to unfavorable conditions for micelle formation at the higher temperatures. In some cases, the long-chain surfactants will even decompose at more than 150°C. Low synthetic temperatures result in imperfectly condensed mesoporous walls with large amounts of terminal hydroxyl groups which make the mesostructure unstable, especially under hydrothermal or steam conditions. It can be expected that increasing the crystallization temperature will enhance the level of silica condensation. In order to prepare ordered mesoporous materials at high temperatures, high temperature-resistant fluorocarbon surfactant (FC-4) is used together with triblock...