Nano-Fibrillar Ceramics by Gas Phase Reduction

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

In this project, a newly-discovered, inexpensive gas/solid reduction process will be examined for creating nanofibrillar structures with organized nanopore channels on surfaces of dense, semiconducting titanium dioxide. The influence of the starting titanium dioxide structure (e.g., amorphous, anatase, or rutile forms), the crystallographic orientation (i.e., single crystals of rutile with varied orientations), and solid-solution additives, on the orientation and morphology of the resulting nanofibers will be carefully examined with the use of scanning and transmission electron microscopy. The rate-limiting step(s) for the steady-state, gas-phase reduction of nanofibrillar oxide will be evaluated by examining the influence of time, temperature, gas flow rates, and gas atmospheres on the extent of reduction (as determined by thermogravimetric analyses and electron microscopy of cross-sections). Finally, electrical properties of the nanofibrillar structures will be investigated and modeled based on the so-called lumped parameter complex plane analysis (LP/CPA) of the ac electrical data. Sensing and catalytic reactivity of the nanofibrrillar structures will also be tested. The proposed approach is a very inexpensive method for fabrication of nano-structured ceramic platform for various applications, particularly for chemical sensing and catalysis. To enable more widespread use of the method, a fundamental understanding of the mechanism of fiber formation is needed so that critical process variables can be identified. The proposed approach integrates cutting-edge resources in ceramic processing, microscopy, modeling and testing of sensing and catalytic properties. Other potential applications of such platforms include photonic crystals and photo-optical devices. Moreover, the proposed process may also open a new avenue for micro-/nano-machining of ceramics, which is a non-trivial task.