Novel electrocatalytic sensors

Basic principles employed for previously developed oxygen and SO{sub 2} sensors have been applied to other chemical sensor needs. Oxide electrodes used for oxygen sensors also possess novel catalytic properties that have been utilized for CO detection through the use of electrocatalysts on solid electrolyte membranes. These oxides offer the ability to catalyze reactions selectively for oxidation and/or reduction of analyte gas species. A combination of a catalytic and noncatalytic electrode deposited on a solid electrolyte was used to sense the reactive species by locally changing the oxygen concentration on the electrode surfaces. Multiple species can be sensed on a single substrate through the use of different electrocatalysts. A related concept is to control the catalytic properties of these materials by controlling the oxygen stoichiometry using an electrochemical pump. Presence of a gas species was sensed by changes in the electronic conductivity of the semiconducting electrode layer