MULTIFUNCTIONAL POTENTIOMETRIC GAS SENSOR ARRAY WITH AN INTEGRATED HEATER AND TEMPERATURE SENSORS

摘要

Solid-state potentiometric gas sensors show much promise for detecting pollutants such as NO{sub}x, CO, and hydrocarbons in ppm level concentrations for exhaust monitoring. The selectivity of these sensors varies with temperature; therefore, sensor arrays can be constructed with integrated heaters to control the temperature of each sensing electrode. The array signals can then be entered into linear algorithms to determine the concentrations of individual species. The array consisted of two La{sub}2CuO{sub}4 electrodes and a Platinum reference electrode all on the same side of a rectangular, tape-cast YSZ substrate. Platinum resistor elements were used as heaters and/or temperature sensors to control and monitor the temperature of the sensing electrodes. Finite Element Modeling was used to predict temperature profiles within the array. The array was then designed to keep one La{sub}2CuO{sub}4 electrode hot with respect to the other two electrodes. The sensor array configuration avoids complexities that might increase manufacturing costs as found in other designs because all electrodes are in the same gas environment with heater and temperature sensors on the opposite side of the substrate. The results of this work demonstrate that a gas sensor array with sensing electrodes kept at different temperatures can yield a device capable of selectively determining NO and NO{sub}2 concentrations.