The electrochemical formula of the gas detector
A considerable part of its flammable, toxic and harmful gases are electrochemically active and can be electrochemically oxidized or reduced. Using these reactions, gas components can be distinguished and gas concentrations can be detected. There are many subcategories of electrochemical gas sensors:
(1) Primary battery-type gas sensors (also known as: Gavoni battery-type gas sensors, fuel cell-type gas sensors, and spontaneous battery-type gas sensors), their principle is the same as that of dry batteries we use, but, The carbon-manganese electrodes of the battery are replaced by gas electrodes. In the case of an oxygen sensor, oxygen is reduced at the cathode and electrons flow through the ammeter to the anode where the lead metal is oxidized. The magnitude of the current is directly related to the concentration of oxygen. This sensor can effectively detect oxygen, sulfur dioxide, chlorine, etc.
(2) Constant potential electrolytic cell type gas sensor. This sensor is very effective for detecting reducing gases. Its principle is different from that of the original battery type sensor. Its electrochemical reaction occurs under the force of current. It is a A true coulometric sensor. This sensor has been successfully used in the detection of carbon monoxide, hydrogen sulfide, hydrogen, ammonia, hydrazine, and other gases, and is the mainstream sensor for the detection of existing toxic and harmful gases.
(3) Concentration battery type gas sensor, the electrochemically active gas will spontaneously form a concentration electromotive force on both sides of the electrochemical cell, and the magnitude of the electromotive force is related to the concentration of the gas. The successful example of this sensor is the automobile Oxygen sensor, solid electrolyte carbon dioxide sensor.
(4), limiting current type gas sensor, there is a sensor for measuring oxygen concentration, which uses the principle that the limiting current in the electrochemical cell is related to the carrier concentration to prepare an oxygen (gas) concentration sensor, which is used for oxygen detection of automobiles and molten steel Oxygen concentration detection.
