Controlled Synthesis of Mesoporous Silicon Oxynitride Ceramics by Nitridization of Mesoporous Organosilicas

非技术描述。氮氧化硅是具有高机械和热强度以及化学稳定性的陶瓷材料。合成氮氧化硅（SONs）与纳米和纳米多孔结构，结构与一个？直径为人类头发丝的千分之一，生产高表面积高效催化剂，过滤膜，传感器，纳米电子薄膜器件和介电材料纳米电子应用。本项目将研究合理、简便的合成方法，包括对预先制备的介孔金属氧化物如有机硅的可控氮化，并开发可调介孔氮氧化硅（SON）材料和薄膜。通过合成具有纳米级和纳米多孔结构以及可变组成和结构的SON，将有可能改善它们的性质，例如表面积、介电常数、量子限制和发光。这些增强将进一步提高它们的催化效率和性能，用于栅极介电器件和光子晶体波导。通过了解各种介孔有机硅上氮化的动力学和机理，最终将产生具有可调纳米结构和性能的SON的低成本合成方法。该方法还可以进一步适用于其它陶瓷材料，例如碳化硅和碳氧化硅陶瓷。该项目将允许培训本科生，包括少数民族学生和研究生积极参与学习固态陶瓷纳米材料合成和理解结构-性能关系。学生？预计该项目的成果还将产生出版物并在国家会议上介绍。技术说明。陶瓷是具有有趣的机械、热、化学和光学性质的多种材料，具有广泛的潜在应用。它们的高强度和热稳定性使其成为高强度使用和磨损产品的理想选择，如高速球轴承和切削刀具刀片。近年来，对氮氧化硅（SON）陶瓷的研究已经瞄准了包括催化在内的新应用，其中固体SON陶瓷参与碱催化的化学反应。人们的注意力也转向了对这些材料在纳米级应用中的研究，其中材料的尺寸是人类头发宽度的1/1000。Asefa教授的这个项目正在探索特殊类型的陶瓷，即由纳米多孔氮氧化硅制成的陶瓷，用于催化，过滤膜，传感器和纳米电子薄膜器件以及金属氧化物半导体（MOS）集成电路的介电材料。目前合成纳米结构氮氧化硅的方法并不是最佳的-它们需要苛刻的条件，并且导致其结构不像所要求的那样一致和均匀的产品。本计画将发展合理且简易的合成方法，包括将预先制备的介孔有机硅控制氮化成可调介孔氮氧化硅材料及薄膜。这些方法有望产生具有可变组成和结构的纳米结构和纳米多孔陶瓷，并改善诸如表面积、介电常数、量子限制和发光等性能。这些增强将进一步提高它们在固体基催化、栅介质器件和光子晶体波导中的效率。包括少数民族学生在内的本科生和研究生将积极参与拟议的项目，他们将学习固态陶瓷纳米材料的合成和理解纳米陶瓷的结构-性能关系。学生们将在系里展示他们的研究成果？的本科生研讨会和美国化学学会区域会议。

NON-TECHNICAL DESCRIPTION. Silicon oxynitrides are ceramic materials that have high mechanical and thermal strength and chemical stability. The synthesis of silicon oxynitrides (SONs) with nanoscale and nanoporous structures, structures with one?thousandths of the diameter of a human hair, produces high surface area efficient catalysts, filtration membranes, sensors, nanoelectronics thin film devices and dielectric materials nanoelectronics applications. In this project, rational and facile synthetic methods involving controlled nitridization of pre-made mesoporous metal oxides such as organosilicas will be investigated and tunable mesoporous silicon oxynitride (SON) materials and thin films will be developed. By synthesizing SON with nanoscale and nanoporous structures and variable compositions and structures, it will be possible to improve their properties such as surface areas, dielectric constants, quantum confinement and luminescence. These enhancements will further improve their catalytic efficiency and properties for applications in gate dielectric devices, and photonic crystal waveguides. By understanding the kinetics and mechanisms of nitridization on various mesoporous organosilicas, low cost synthetic methods to SONs with tunable nanostructures and properties will ultimately result. The method can also further be adapted to other ceramic materials such as silicon carbides and silicon oxycarbide ceramics. The project will allow the training of undergraduate students, including minority students, and graduate students to be actively involved to learn solid-state ceramic nanomaterials synthesis and understand structure-property relationships. The students? results in this project are expected also to generate publications and be presented at national conferences. TECHNICAL DESCRIPTION. Ceramics are diverse materials with interesting mechanical, thermal, chemical, and optical properties and possessing a wide range of potential applications. Their high strength and thermal stability make them ideal for products subject to heavy use and wear and tear such as high speed ball bearings and cutting tool inserts. In recent years, research on silicon oxynitride (SON) ceramics has targeted novel applications including catalysis, where the solid SON ceramic participates in base-catalyzed chemical reactions. Attention has also turned to investigations of these materials in nanoscale applications, where the size of the material is 1/1000th of the width of a human hair. This project by Professor Asefa is exploring special type of ceramics, those made from nanoporous silicon oxynitrides, in applications such as catalysis, filtration membranes, sensors, and nanoelectronics thin film devices and dielectric materials for metal-oxide-semiconductor (MOS) integrated circuits. Current methods to synthesize nanostructured silicon oxynitrides are not optimum - they require harsh conditions and result in products whose structures are not as consistent and uniform as required. In this project, rational and facile synthetic methods involving controlled nitridization of pre-made mesoporous organosilca into tunable mesoporous silicon oxynitride materials and thin films will be developed. The approaches are expected to result in nanostructured and nanoporous ceramics having variable compositions and structures, and improved properties such as surface areas, dielectric constants, quantum confinement and luminescence. These enhancements will further improve their efficiency for solid-base catalysis, gate dielectric devices, and photonic crystal waveguides. Undergraduate students, including minority students, and graduate students will be actively involved in the proposed project and they will learn solid-state ceramic nanomaterials synthesis and understanding structure-property relationships nanoceramics. The students will present their research results at the department?s undergraduate seminars and at the American Chemical Society Regional Meetings.