Development of Agile Titania Sensors Via High-Temperature Reductive Etching Process (HiTREP©): I. Structural Reorganization
Abstract:High selectivity, enhanced sensitivity, short response times and long shelf-life are much sought-after features in solid-state chemical sensors for the detection and metering of gas(es) of interest. Because the sensing mechanism of semiconducting oxides is invariably surface dominated, benign microscopic features are desirable to realize a useful sensing material. In principle, such morphological features could be incorporated in a number of semiconducting oxides by employing a technique based on thermodynamic consideration of the metal/metal oxide coexistence. By dynamically modulating the equilibrium oxygen partial pressure across the metal/metal oxide proximity line, renewed formulation and growth of an oxide surface on an atomic/submolecular level with exotic morphological features under conditions of oxygen “deprivation” or “enrichment” has been achieved practically in a number of potential ceramic sensor systems. In the case of oxides that are not amenable to such classical oxygen partial pressure modulation, a novel high-temperature reductive etching process (HiTREP©) could be exploited to recreate the smart nanofeatures to impart the desired accentuation effect. This surface modification method was applied to a new commercially available aqueous plasma electro-deposited (PED) titania thick film, and the microscopic results of this strategy are presented.
Document Type: Research Article
Affiliations: 1: Department of Chemical Engineering (MS 305), The University of Toledo, Toledo, Ohio 43606 2: Henkel Corporation, 32100 Stephenson Highway, Madison Heights, Michigan 48071 3: Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210
Publication date: 2008-09-01