(163r) Conductivity and Gas Sensing Properties of Nanocluster Iron Oxide Aerogel

The present work aims to probe the surface conductivity of iron oxide pasted on a gold-electrode sensor substrate and evaluate its sensing performance to volatile organic compounds (VOCs). The iron oxide material was made via synthesis by sol-gel chemistry and drying in a supercritical fluid process, and the powders were measured by FESEM to be 10-30 nm for small particles and up to 250 nm for large clusters. The conductivity of the material was shown to increase largely in the environment of dry to humid air as well as under illumination of ultraviolet light. The VOC gases used for sensor analysis were methanol, iso-propanol, acetone, methane and toluene, respectively, and the sensitivity was revealed to be dependent upon the molecular structure of the detected gas. Effects of gaseous oxygen and moisture concentrations were studied in order to understand the interaction of lattice oxygen ions with the organic molecules near the oxide surface. Kinetic analysis for the sensing behavior is in progress.