Abstract: An apparatus for the detection and measurement of an object gas is disclosed. Such an apparatus comprises a sensing electrode having a catalytic surface, a counter electrode having a catalytic surface, an electrolyte in electrical contact with the sensing electrode and the counter electrode, a reference electrode in contact with the electrolyte and the sensing electrode, a means for supplying an electrical potential between the sensing electrode and the reference electrode and a means for measuring the current flow resulting from the reaction of the object gas with the sensing electrode by way of the sensing electrode substrate to the counter electrode substrate. The substrate, which supports the catalytic sensing electrode and counter electrode materials being electrically conductive carbon or graphite, which allows the electrons generated at the sensing electrode catalytic surface to be removed through the substrate instead of from the surface.

Abstract: The present invention discloses the use of gold oxide as a catalyst for use in a hydrogen sulfide gas detector. The gold oxide catalytic surface being supported on an electrically conductive substrate; thereby allowing the flow of electrons between the anode and the cathode to occur between the substrates of the electrodes instead of the catalytic surfaces. This will reduce the amount of catalytic material required to form the electrode, and will not require that the catalytic surface be an electrical continuum.