Influence of Adsorption and Catalytic Reaction on Sensing Properties of a Potentiometric La[sub 2]CuO[sub 4]∕YSZ∕Pt Sensor

Abstract

This study describes the gas-sensing properties of a La 2 CuO 4 /yttria-stabilized zirconia ͑YSZ͒/Pt potentiometric sensor and discusses its sensing mechanism in terms of the adsorptive and catalytic behavior of the electrode materials. The sensor is highly sensitive to NO, CO, and NO 2 , but virtually no response is observed for CO 2 and O 2 detection. Optimal NO sensing is obtained at ϳ450°C. Above 500°C, there is an abrupt decrease in sensitivity. Below 400°C, there is a saturation of the response. The sensor is NO selective against O 2 , but its sensitivity is affected significantly by CO 2 and CO. This selectivity behavior is in good agreement with temperature-programmed desorption results, indicating that the NO response is very likely adsorption-related. For example, the NO chemisorption peak disappears in the presence of CO 2 , which agrees with the sensor results showing a significant decrease in the NO sensitivity by CO 2 addition even though CO 2 itself shows no sensor response.

Coupled Metal Oxide-Doped Pt/SnO2Semiconductor and Yittria-Stabilized Zirconia Electrochemical Sensors for Detection of VOCs

“…The metal oxides may act as a crystal growth inhibitor. 27,28 The crystallite size of SnO 2 evaluated from the XRD patterns, using Sherrer's equation, are summarized in Table I. When 1 wt% Pt is impregnated onto the SnO 2 , its average crystallite size doubles.…”

La2CuO4 sensing electrode configuration influence on sensitivity and selectivity for a multifunctional potentiometric gas sensor

“…In addition, it is non-catalytic for the reduction of NO [6] and highly catalytic for the reduction of NO 2 and oxidation of CO [7]. La 2 CuO 4 powders were synthesized via an amorphous citrate gel combustion method [8].…”

Exploration of Electric-Field Effects in Solid State Ionic Devices

“…From this past work, the primary mechanism for NO and NO 2 sensitivity has been concluded to occur as a result of surface complex formation, which either injects electrons or holes into the p-type LCO thereby changing the Fermi level and thus potential of the semiconductor. 5,9,13,14 The change in chemisorptive properties due to the presence of an electric field was first described as the "electroadsorptive" effect by Wolkenstein in 1955. 15 Fifty plus years of subsequent UHV surface measurements and atomistic computational modeling efforts have corroborated Wolkenstein's theories.…”