Electrochemical sensor

Based on electrochemical oxidation-reduction reactions, the core consists of a working electrode, a counter electrode, and an electrolyte. Carbon monoxide is oxidized to carbon dioxide at the working electrode, releasing electrons to form an electric current, and the current intensity is proportional to the concentration. Its advantages lie in high sensitivity (detection limit up to 1ppm), linear output, fast response, and low cost. Typical applications include home gas alarms, industrial safety monitoring, and portable detectors. However, attention should be paid to the lifespan limitation caused by electrolyte evaporation (usually 2-3 years), and it is susceptible to interference gases such as sulfides.

Semiconductor sensors

Using metal oxides such as tin dioxide (SnO ₂) as sensitive materials, the concentration is detected through resistance changes caused by gas adsorption. After carbon monoxide adsorption, the electron density on the semiconductor surface increases and the resistance decreases, and the change is concentration dependent. Its advantages are low cost, simple structure, and suitability for consumer grade products such as smart home alarms. But the disadvantages are significant: poor selectivity (susceptible to interference from ethanol, hydrogen, etc.), insufficient stability (drift caused by humidity/temperature changes), and the need for regular heating and cleaning to maintain performance, with a short lifespan (usually 1-2 years).

infrared sensor

By utilizing the absorption characteristics of carbon monoxide for specific wavelengths of infrared light (such as the 4.6 μ m band), the concentration can be calculated by measuring the attenuation of light intensity. Its core consists of an infrared light source, an air chamber, and a detector, using a dual wavelength design to eliminate environmental interference. The advantages include high precision (error<± 2%), long lifespan (>5 years), strong anti-interference ability, and no need for regular calibration. But the cost is higher (3-5 times that of electrochemical sensors), the volume is larger, and it is mostly used in industrial process control, environmental monitoring and other scenarios that require strict accuracy.

Summary: Electrochemical sensors have comprehensive performance and are suitable for most civilian and industrial scenarios; Semiconductor sensors are suitable for low-cost and simple applications; Infrared sensors are positioned in the professional market.