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强度、热强度和化学稳定性的陶瓷材料。具有纳米级和纳米多孔结构（其结构的直径为人类头发千分之一）的氮氧化硅（SON）的合成可产生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。在该项目中，将研究涉及有机硅等预制介孔金属氧化物的受控氮化的合理且简便的合成方法，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成分和结构的SON，将有可能改善其表面积、介电常数、量子限制和发光等性能。这些增强功能将进一步提高其在栅极介电器件和光子晶体波导中的应用的催化效率和性能。通过了解各种介孔有机二氧化硅的氮化动力学和机制，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他陶瓷材料，例如碳化硅和碳氧化硅陶瓷。该项目将培养本科生（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的合成并了解结构与性能之间的关系。学生们？预计该项目的成果也将出版并在国家会议上介绍。技术说明。陶瓷是多种材料，具有有趣的机械、热、化学和光学特性，具有广泛的潜在应用。它们的高强度和热稳定性使其非常适合频繁使用和磨损的产品，例如高速球轴承和切削刀具刀片。近年来，氮氧化硅（SON）陶瓷的研究瞄准了包括催化在内的新颖应用，其中固体SON陶瓷参与碱催化化学反应。人们的注意力也转向了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由纳米多孔氮氧化硅制成的特殊类型陶瓷在催化、过滤膜、传感器、纳米电子薄膜器件和金属氧化物半导体 (MOS) 集成电路介电材料等应用中的应用。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，并且导致产品的结构不符合要求的一致和均匀。在该项目中，将开发合理且简便的合成方法，包括将预制介孔有机二氧化硅受控氮化成可调介孔氮氧化硅材料和薄膜。这些方法预计将产生具有可变成分和结构的纳米结构和纳米多孔陶瓷，并改善表面积、介电常数、量子限制和发光等性能。这些增强功能将进一步提高固基催化、栅极介电器件和光子晶体波导的效率。包括少数民族学生在内的本科生和研究生将积极参与该项目，他们将学习固态陶瓷纳米材料的合成并了解纳米陶瓷的结构-性能关系。学生们将在该系的本科生研讨会和美国化学会区域会议上展示他们的研究成果。

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.