Summary: Ceramic Materials and Nano-structures for Chemical Sensing
Department of Chemical and Environmental Engineering
The University of Toledo, 3052 Nitschke Hall, Toledo, OH 43606-3390.
Sheikh A. Akbar
Department of Materials Science and Engineering
The Ohio State University, 2041 Watts Hall, College Road, Columbus, OH 43210.
High selectivity, enhanced sensitivity, short response time and long shelf-life are some of the key features sought in the
solid-state ceramic-based chemical sensors. Since the sensing mechanism and catalytic activity are predominantly
surface-dominated, benign surface features in terms of higher aspect ratio, large surface area and, open and connected
porosity, are required to realize a successful material. In order to incorporate these morphological features, a technique
based on rigorous thermodynamic consideration of the metal/metal oxide coexistence, is described. By modulating the
oxygen partial pressure across the equilibrium M/MO proximity line, formation and growth of new oxide surface on an
atomic/ submolecular level under conditions of `oxygen deprivation', with exotic morphological features has been
achieved in a number of metal oxides that are potential sensor materials. This paper describes the methodology and
discusses the results obtained in the case of two model systems, viz., tungsten oxide (WO3) and titanium oxide (TiO2).
Key words: Semiconducting ceramic oxides, Redox reactions, Microstructure, Chemical sensors