SGER: Exploratory Study on Low Temperature Synthesis of Nanostructured Particles by a Novel Aero-Sol-Gel Process

SGER：新型气溶胶凝胶工艺低温合成纳米结构颗粒的探索性研究

• 批准号: 9730535
• 负责人: Gregory Beaucage
• 金额: $ 5万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-11-01 至 1998-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9730535&HistoricalAwards=false
• 关键词: SGER; Exploratory; Study; Low; Temperature

SUMMARY CTS-9730535 Exploratory Study on Low Temperature Synthesis of Nanostructured Particles By a Novel Aero-Sol-Gel Process G. Beaucage, Asst. Professor of Materials Science and Engineering, PI S.E. Pratsinis, Professor of Chemical Engineering, Co-PI University of Cincinnati, Cincinnati, OH 45221-0012 The goal of this project is to investigate the feasibility of novel, room temperature process for synthesis of nanoparticles by carrying our sol-gel reactions in the aerosol phase. A first experimental base will be created with silica and titania nanoparticles. Preliminary experiments have resulted in pure silica nanoparticles (by mass spectroscopy) with specific surface areas comparable to aerogels. These analyses show primary particles smaller than 1.5 nm in diameter aggregated into classical diffusion-limited-aggregates of approximately 30nm with a mass fractal dimension close to 2.5. Such aggregates have long been sought in the hope of developing catalysis supports with the maximum possible surface area. Conventional pyrolytic methods (e.g. flame reactors) are not capable of such morphologies since the primary particles are about an order of magnitude larger. The proposed process involves an exceedingly simple and cost effective approach which borrows from both sol-gel chemistry and laminar flow, pyrolytic (flame) aerosol techniques. In preliminary experiments, sol-gel precursors such as tetraethoxysilane (TEOS) along with other reactants are dispersed in the gas phase in a closely controllled mode using a flow chamber similar to those encountered in flame reactors. Here, however, there is no flame and the entire apparatus is constructed form PVC plastic tubing, rather than quartz of alloys, costing only about $100. In spite of the simplicity of the initial set-up, some degree of control has already been achieved on the nanoscale by variation of the precursor concentration, type and flow rates.

摘要CTS-9730535新型气溶胶-凝胶法低温合成纳米结构粒子的探索性研究。材料科学与工程助理教授G.Beucage，材料科学与工程教授PiS.E.Pratsinis，化学工程教授，辛辛那提大学化学工程教授，俄亥俄州辛辛那提45221-0012.本项目的目标是探索通过在气溶胶相中进行我们的溶胶凝胶反应，在室温下合成纳米颗粒的新工艺的可行性。第一个实验基地将用二氧化硅和二氧化钛纳米颗粒创建。初步实验已经得到了纯二氧化硅纳米颗粒(通过质谱分析)，其比表面积与气凝胶相当。这些分析表明，直径小于1.5 nm的初级粒子聚集成约30 nm的经典扩散限制聚集体，质量分维接近2.5。长期以来，人们一直在寻找这样的聚集体，希望开发出具有最大可能表面积的催化载体。传统的热解方法(如火焰反应器)不能形成这种形态，因为初级颗粒大约大一个数量级。拟议的工艺涉及一种极其简单且具有成本效益的方法，该方法借鉴了溶胶-凝胶化学和层流、热解(火焰)气溶胶技术。在初步实验中，使用类似于火焰反应器中遇到的流动室，将正硅酸乙酯(TEOS)等溶胶-凝胶前体以及其他反应物以严格控制的方式分散在气相中。然而，这里没有火焰，整个装置是由聚氯乙烯塑料管建造的，而不是合金石英，成本仅为100美元左右。尽管初始设置很简单，但通过改变前体浓度、类型和流速，已经在纳米尺度上实现了一定程度的控制。