Electrically biased two electrode, electrochemical gas sensor with a H.sub.2

Abstract

Abstract The instant invention relates to an electrochemical sensor for detecting gases or vapors such as carbon monoxide, alcohol NOX etc. The gas sensor includes either a solid polymer ion-exchange-membrane electrolyte or a liquid electrolyte adsorbed in a suitable matrix, a catalytic sensor electrode and a combination counter/reference electrode. A biasing voltage is applied between the electrodes. The biasing voltage is made equal to or larger than the oxidation/reduction potential of a platinum/air electrode and is also greater than the reversible oxidation/reduction potential of the gas or vapor to be detected. As a result, the gas or vapor to be detected is rapidly oxidized at the sensor electrode to produce a current proportional to the mass of the gas present in the incoming stream, while at the same time, making the device insensitive to air. The counter/reference electrode is of a novel construction to provide optimum reversible hydrogen evolution and a hydrogen buffering or storage arrangement to maintain the reference electrode potential substantially constant at 0.0 volts. The electrode is fabricated of a noble metal alloy. Associated with the electrode is a perforated foil such as palladium which has a high solubility for hydrogen. The molecular hydrogen produced at the counter/reference electrode is absorbed in the palladium. An invariant hydrogen atmosphere is thus maintained at the counter/reference electrode so that the reference electrode voltage is kept substantially at zero volts.

Inventors

• 👤 Anthony B. LaConti

Bibliographic Details