. 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.
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.
This NSF-funded research project has enabled the PI and his team to make major contributions to the field of nanostructured ceramic materials. Over the last few years, through this project the PI’s group has successfully developed various, facile synthetic methods leading to a range of novel nanostructured ceramics possessing unique and tunable physical, chemical magnetic, catalytic and electrocatalytic properties. Moreover, using these materials as model nanoscale systems, the PI and his group have discovered many fundamental properties of ceramc materials at nanoscale sizes and unravelled many of theoir structure-property correlations. This can be seen from the many (over 25) peer-reviewed, high impact publications the project resulted over the past four years. Moreover, thanks to their ceramic composition, many of the resulting nanomaterials were found to be not only efficient catalytsts and electrocatalysts but also robust, stable and easily recyclable and reusable (electro)catalysts for various reactions that are pertinent to renewable energy and fuel cell applications. In addition, the materials have been demonstrated to be technologically useful as part of electrodes of fuel cells, for hydrogen production from water, for energy storage and dye-sensitized solar cell devices. This has resulted in three patent applications. Owing to their unprecedented and remarkable catalytic activities in fuel cells and for water splitting producing hydrogen (a clean fuel) from water, some of these ceramic nanomaterials developed by the PI and his group have recently received a wide range of media coverage and public interests as well. The project’s broader and educational impacts have also been successfully achieved. For instance, the project allowed the PI to train many undergraduate, graduate and post-doctoral students with various chemical synthesis, state-of-the-art instrumentation chemical analysis and data interpretation. Some of these students have already embarked their own independent career as professors elsewhere now while others started their graduate studies. The project has additionally helped the recruitment of various under-represented students in sciences and engineering to be involved in research. The work has given opportunities to some of these students as well as the PI to give oral and poster presentations at various international and local symposiums and conferences. In addition, the project enabled the PIs to enhance his teaching activities and curricula, particularly in advanced inorganic chemistry and materials chemistry and pharmaceutical materials engineering courses he has been teaching recently to undergraduate and graduate students. Finally, the results obtained form this project has enabled the PI to start and expand upon an array of collaborative research projects with major international research institutions around the world, including Korea, Brazil and China. These new interdisciplinary studies among researchers will be expected to help not only the training of internationally-exposed work-force but also provide new insights and perspectives to the students involved in future projects in the PI’s laboratory in the areas of renewable energy, energy storage and batteries and fuel cells.
