Electrochemical gas sensor

Abstract

Disclosed is an electrochemical gas sensor wherein interference errors are minimized. In an electrochemical gas sensor wherein an object gas to be sensed is taken into an electrolyte solution through an air-permeable membrane and an electrical signal corresponding to the concentration of the object gas is output, an air-permeable membrane (4) constituting a working electrode member (4') is made of a kneaded body of a carbon black fine powder and a fluororesin fine powder, and an electrode catalyst layer (13) is formed on a side of the air-permeable membrane (4) which side faces an electrolyte solution (6).

Description

technical field [0001] The invention relates to an electrochemical gas sensor which introduces the gas to be detected through a gas-permeable diaphragm and takes the oxidation and reduction currents generated between the working electrode part and the counter electrode part as detection signals. Background technique [0002] The electrochemical gas sensor is constructed in such a way that a porous polytetrafluoroethylene membrane through which gas can pass is tensioned on a part of a container storing an electrolyte, and a pair of holes is formed on the electrolyte side of the porous polytetrafluoroethylene membrane. The detection gas has a catalytic function and a conductive catalytic electrode layer, and detects an electrolytic current flowing between the catalytic electrode layer and a counter electrode member spaced apart from the catalytic electrode layer. [0003] If the electrochemical gas sensor is used to detect arsine (AsH 3 ), phosphine (PH 3 ), silane (SiH 4 )...

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Problems solved by technology

[0007] In this way, the lead part is arranged in contact with the working electrode, so the lead part is also in contact with the electrolyte. When the electrolyte is a strongly acidic substance, it is necessary to use noble metals such as platinum in terms of corrosion resistance, resulting in an increase in cost. It leaks from the small gap between the lead part and the diaphragm (working electrode), so there are problems such as the need for a strict sealing structure

[0008] In addition, the gas sensor disclosed in Patent Document 1 is basically a sensor using a hydrophobic porous membrane formed by dispersing a conductive substance in polytetrafluoroethylene as a detection electrode (working electrode). Formed, and the conductor is in contact with the hydrophobic porous membrane to take out the detection signal, but since the hydrophobic porous membrane is formed in a tubular shape, a special structure is required to introduce the gas to be detected or to seal the electrolyte, resulting in complicated structure

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