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Nano-fibrillar Ceramics by Gas Phase Reduction S. Akbar, Ohio State University; K. Sandhage, Georgia Institute of Technology DMR- 0309558.
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Nano-fibrillar Ceramics by Gas Phase ReductionS. Akbar, Ohio State University; K. Sandhage, Georgia Institute of Technology DMR- 0309558 Aligned arrays of single crystal TiO2 nano-fibers (20 nm dia.) are synthesized by a simple heat treatment in H2-bearing gas. During H2 treatment, TiO2 surfaces undergo highly anisotropic etching (“nanocarving”), so as to create aligned ceramic nanofibers. During TiO2 etching, H2 reacts with oxygen on the surface and forms H2O. The H2O then migrates into the gas. The remaining Ti associated with the lost oxygen migrates back into the bulk TiO2. When the concentration of this back-migrating Ti reaches a maximum value, no more Ti can migrate into the bulk TiO2 and the etching stops. This “nanocarving” technique is a low-cost, highly-scalable method of fabricating aligned arrays of nano-sized ceramic fibers. Nanofiber-covered surfaces possess much higher surface areas than flat ceramic surfaces, which can enhance the rate of reactions on the surface (e.g., for enhanced gas sensing, photo-catalysis and water purification). 001 H2 H2O TiO2 Etching Process H2 O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O O Ti O O Ti O O Ti O O Ti O O Ti O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O O Ti O
Nano-fibrillar Ceramics by Gas Phase ReductionS. Akbar, Ohio State University; K. Sandhage, Georgia Institute of Technology DMR- 0309558 • Educational and Broader Impact Activities: • The results from this project are being readily integrated into the lecture materials of two newly developed courses at OSU (MSE 673: Sensor Materials – a Multidisciplinary Approach and the IGERT course, MSE 694A: Introduction to Molecular Engineering of Micro-devices), as well at GATech (MSE 4803/8803: Nano-materials and Nano-fabrication and Eng 1001: Introduction to Engineering). Students (undergraduate and graduate) are taking these courses and applying them toward core or technical electives as required by their degree program. The OSU courses have been integrated into the newly developed “Electronic Materials” track of the undergraduate degree program in the Department of Materials Science and Engineering. The GATech MSE 4803/8803 course is one of the required classes for a newly-established Nanomaterials Certificate program for undergraduates. • Ms. Chia-Yun Chou at OSU completed her undergraduate senior thesis project, where she employed the nano-fibrillar structure as a platform for sensing reducing gases such as H2 and CO. • The results are also being disseminated by publications in peer-reviewed journals (Advanced Materials, 16[3], 260-264 (2004); Ceramics International, 30[7], 1121-26 (2004)) and presentations at national (Cocoa Beach meeting of ACerS) and international meetings (ICMAT in Singapore and IMCS in Japan).