CAREER: Synthesis and Characterization of Metal/Silica Multicomponent Classes by the Sol-Gel Process

职业：通过溶胶-凝胶工艺合成和表征金属/二氧化硅多组分类

• 批准号: 9623570
• 负责人: Albert Stiegman
• 金额: $ 34.92万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-15 至 2000-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9623570&HistoricalAwards=false
• 关键词: CAREER; Synthesis; Characterization; Metal; Silica

Abstract 9623570 Stiegman The two principal goals of this research are to advance study of the chemical parameters that effect the synthesis and processing of multicomponent glasses by the sol-gel process, and to fabricate and characterize entirely new metal/silica multicomponent glasses. Three primary activities will be conducted: 1. The synthesis of new metal/silica xerogels. Several metal and metal-centered functional groups will be incorporated into the silica xerogel matrix using the synthetic protocol established for the oxovanadium materials. Central to this effort is the optimization of conditions to insure homogeneity for each metal. The metals chosen for incorporation will be based on their anticipated reactivity and on their position as part of a series of systematically varying materials for the elucidation of structure-property relationships. 2. Elucidation of the chemistry of the sol-gel process under multicomponent conditions. This will involve determining the effects of the metal on the kinetics and mechanism of gelation, the processes of aging, drying and stabilization. This will provide a fundamental understanding of the chemical processes that occur in the solgel process when many kinetically different components are present. 3. Characterization of the properties and reactivity of the new multicomponent glasses. The characterization of the hybrid materials will entail two primary activities: (1) characterization of the coordination geometry and electronic structure of the metal center as it is found in the silica matrix; and (2) characterization of the physical and morphological properties of the bulk xerogel. %%% Homogeneous multicomponent glasses, comprised of differing ratios of metal and semimetal oxides, have attracted considerable attention due to their diverse and potentially useful properties and reactivities. Among the applications predicted for these materials are as heterogeneous catalysts, chemical sensors and environmental monitors, and optical and electronics components. While the sol-gel process has been used successfully to prepare specific materials, problems have precluded its general employment as a method for preparing homogeneous hybrid glasses. These problems arise from the widely differing gelation kinetics of the various constituents and by the many variables associated with aging and drying these materials; all of which can lead to heterogeneity in the final product. The aim of this work is to optimize the conditions needed to produce a homogeneous glass, and provide a detailed and comprehensive picture of the formation and properties of hybrid metal/silica glasses to contribute significantly to bringing this class of materials into the sphere of real applications.

摘要 9623570 斯蒂格曼 本研究的两个主要目标是推进研究的化学参数，影响合成和加工的多组分玻璃的溶胶-凝胶过程中，制造和表征全新的金属/二氧化硅多组分玻璃。 将开展三项主要活动： 1.新型金属/二氧化硅干凝胶的合成。几种金属和金属为中心的官能团将被纳入二氧化硅干凝胶基质使用的合成协议建立的氧钒材料。这项工作的核心是优化条件，以确保每种金属的均匀性。 选择用于掺入的金属将基于它们的预期反应性和它们作为用于阐明结构-性质关系的一系列系统变化材料的一部分的位置。 2.多组分条件下溶胶-凝胶过程的化学解释。这将涉及确定金属对凝胶化的动力学和机制、老化、干燥和稳定过程的影响。这将提供一个基本的理解，发生在溶胶-凝胶过程中的化学过程时，许多动力学不同的组件存在。 3.新型多元玻璃的性能和反应活性表征。 杂化材料的表征将需要两个主要的活动：（1）表征金属中心的配位几何形状和电子结构，因为它是在二氧化硅基质中发现的;和（2）本体干凝胶的物理和形态学性质的表征。 由不同比例的金属和半金属氧化物组成的均相多组分玻璃由于其多样性和潜在的有用性质和反应性而引起了相当大的关注。在这些材料的预测应用中，有多相催化剂、化学传感器和 环境监测器以及光学和电子元件。 虽然溶胶-凝胶法已成功地用于制备特定的材料，但存在的问题阻碍了其作为制备均匀混合玻璃的方法的普遍应用。这些问题源于各种成分的凝胶化动力学的广泛差异以及与这些材料的老化和干燥相关的许多变量;所有这些都可能导致最终产品的不均匀性。这项工作的目的是优化生产均匀玻璃所需的条件，并提供混合金属/二氧化硅玻璃的形成和性能的详细和全面的图片，以显着地将这类材料带入真实的应用领域。