Titania-Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity
Abstract:Miniature, potentiometric, solid-state, carbon monoxide (CO) sensors with semiconducting oxide electrodes were investigated over the temperature range 500°–700°C. The effects of the electrochemical properties of the semiconducting oxides, after the addition of a catalyst and an alkaline metal oxide were evaluated in terms of the improvement in selectivity and response time. A sensor with high sensitivity and reversibility was obtained using a combination of an n- (titania) and p-type (composite titania with yttria and palladium) electrode to form a difference in the electrode equilibria. The device was able to measure a wide range of CO concentrations (10–16 000 ppm) with a high sensitivity to CO. A low-cost, rugged device could be fabricated because the sensing and reference electrodes were exposed to the same gaseous atmosphere. The results presented herein were attributed to the differential electrode equilibria mechanism, which comprises both semiconducting response and heterogeneous electrocatalysis contributions to the potentiometric sensor response.
Document Type: Research Article
Affiliations: 1: Department of Advanced Materials Engineering, Sejong University, Seoul 143-747, Korea 2: Department of Chemical and Environmental Engineering, University of Toledo, Toledo, Ohio 43606 3: Department of Materials Science and Engineering, Chonnam National University, Gwangju 550-749, Korea 4: Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611
Publication date: 2010-03-01