Exploring Electrochemical Oxygen Sensors: Core Technologies for Oxygen Detection and Monitoring

Accurate detection and monitoring of oxygen concentration are key to ensuring safety and normal operation in many fields such as industrial production, medical emergency, and environmental monitoring. Electrochemical oxygen sensors have become one of the core technologies for oxygen detection and monitoring due to their high sensitivity, high precision, and fast response. Now, let's delve into how electrochemical oxygen sensors work together.

Working principle of electrochemical oxygen sensor: wonderful conversion of chemical reaction and electrical signal

Electrochemical oxygen sensors are based on the principle of electrochemical reactions to detect oxygen concentration, and their core components include electrodes, electrolytes, and breathable membranes. Sensors mainly have three electrodes: working electrode, counter electrode, and reference electrode, which work together to form a complete electrochemical circuit.

When a gas containing oxygen enters the interior of the sensor through a breathable membrane, oxygen undergoes a reduction reaction on the surface of the working electrode. Taking the common acidic electrolyte environment as an example, oxygen obtains electrons on the working electrode, with the reaction equation: O₂+4H ⁺+4e⁻=2H₂O. During this process, electrons are released from the working electrode and flow towards the counter electrode through an external circuit. At the same time, ions in the electrolyte also undergo directional movement, forming an electric current. Corresponding oxidation reactions will occur on the electrodes to maintain the charge balance of the entire circuit.

The function of the reference electrode is to provide a stable potential reference, ensuring the stability of the working electrode's potential, thereby enabling the electrochemical reaction to proceed stably and ensuring the accuracy of the detection results. The magnitude of the generated current is directly proportional to the number of oxygen molecules involved in the reaction, and the number of oxygen molecules is related to the concentration of oxygen in the environment. Therefore, by measuring the magnitude of the current, the concentration of oxygen can be calculated.

The detection process of electrochemical oxygen sensors: from gas entry to data output

1. Gas diffusion

Gas in the environment diffuses into the interior of the sensor through a breathable membrane. Breathable membrane is a special polymer material that only allows gas molecules to pass through while preventing liquid and solid impurities from entering, thereby protecting the electrodes and electrolyte inside the sensor from contamination and ensuring the normal operation and service life of the sensor.

2. Electrochemical reaction:

After gas enters, an electrochemical reaction occurs on the surface of the working electrode, reducing oxygen and producing electrons and ions. Electrons flow along the external circuit towards the counter electrode, while ions move in the electrolyte, forming an electric current. In this process, the rate of reaction and the magnitude of the generated current depend on the concentration of oxygen. The higher the concentration of oxygen, the more intense the reaction and the greater the generated current.

3. Signal conversion and processing

The current signal generated by the sensor is very weak and needs to be amplified and converted through circuits. The amplified current signal is converted into a voltage signal, which is then converted into a digital signal through analog-to-digital conversion. These digital signals are then processed by a microprocessor, which converts them into corresponding oxygen concentration values according to pre-set algorithms, and displays them on a screen or transmits the data to other devices such as data collectors and control systems through communication interfaces.

Monitoring application of electrochemical oxygen sensors: safeguarding safety and health in various fields

1. Industrial safety monitoring

There are various potential hazards in industrial fields such as petrochemicals, coal mining, and metal smelting. For example, in the petrochemical production process, pipeline leaks may cause combustible gases and oxygen to mix, forming a mixture of gases within the explosive limit range. Once it encounters a fire source, an explosion may occur. Electrochemical oxygen sensors can monitor the oxygen concentration in the environment in real time. When the oxygen concentration is below a safe threshold (such as 19.5%), an alarm is immediately issued to remind staff to take measures to avoid accidents. Meanwhile, in some enclosed spaces such as reaction vessels, storage tanks, etc., sensors can also detect the presence of oxygen deficiency, ensuring the safety of workers' lives.

2. In the field of healthcare

Accurate monitoring of oxygen concentration is crucial in hospital wards, operating rooms, intensive care units, and other places. For patients who require oxygen therapy, doctors need to accurately control the concentration and flow of oxygen based on the patient's condition and physical condition. Electrochemical oxygen sensors can be installed on devices such as oxygen concentrators, ventilators, and oxygen masks to monitor the output concentration of oxygen in real time, ensuring that patients can receive appropriate concentrations of oxygen, improving treatment effectiveness, and safeguarding their life and health. In addition, quickly and accurately detecting the oxygen concentration in the patient's surrounding environment during emergency treatment can also help medical staff take correct emergency measures.

3. Environmental monitoring

Electrochemical oxygen sensors also play an important role in environmental science research and air quality monitoring. Although oxygen is one of the main components in the air, changes in oxygen concentration may have an impact on the ecological environment and human health in certain special environments, such as forest fire sites, landfills, underground caves, etc. By deploying oxygen sensors in these areas, real-time monitoring of changes in oxygen concentration can be achieved, providing data support for environmental research and emergency response. For example, monitoring oxygen concentration at forest fire sites can help firefighters determine the development of the fire and develop firefighting strategies; Monitoring oxygen concentration in landfills can prevent safety accidents caused by the accumulation of harmful gases generated by anaerobic fermentation.

4. Smart Home and Daily Life

With the development of smart home technology, people's attention to indoor air quality is increasing. Electrochemical oxygen sensors can be integrated into smart home systems to monitor indoor oxygen concentration in real-time. When the indoor oxygen concentration decreases due to poor ventilation or other reasons, sensors can automatically activate ventilation equipment to improve indoor air quality and create a comfortable and healthy living environment for people. In addition, in some special places such as basements, wine cellars, etc., sensors can also monitor oxygen concentration to ensure the safety of personnel.

Advantages and Challenges of Electrochemical Oxygen Sensors: Continuously Developing Detection Technologies

Electrochemical oxygen sensors have many significant advantages. It has high sensitivity and accuracy, and can detect small changes in oxygen concentration; Fast response speed, able to output detection results in a short period of time; And the structure is relatively simple, the cost is low, and it is easy to apply on a large scale. Meanwhile, it can also achieve continuous monitoring and provide real-time oxygen concentration data.

However, electrochemical oxygen sensors also face some challenges. Firstly, it is sensitive to environmental conditions, and changes in factors such as temperature, humidity, and pressure may affect the accuracy of detection results. Therefore, temperature compensation and calibration are necessary. Secondly, the electrolyte in the sensor will gradually deplete over time, leading to a decline in sensor performance and limited lifespan, requiring regular replacement. In addition, some interfering gases, such as carbon monoxide, hydrogen sulfide, etc., may react with the sensor and interfere with the detection of oxygen, requiring corresponding anti-interference measures.

In order to overcome these challenges, researchers constantly engage in technological innovation and improvement. For example, developing new electrode materials and electrolytes to improve the stability and service life of sensors; Adopting advanced signal processing technology to improve the anti-interference ability and accuracy of sensors; Research intelligent calibration and compensation methods to reduce the impact of environmental factors on detection results.

Electrochemical oxygen sensors play an irreplaceable role in the field of oxygen detection and monitoring due to their unique working principle and wide applications. With the continuous advancement of technology, it will be applied in more fields, making greater contributions to ensuring people's safety and health and promoting social development.

Why is it necessary to detect the concentration value of oxygen?

Oxygen is closely related to us. For example, the working environment in underground corridors is relatively complex and works underground. The limited space underground has very thin oxygen, which is crucial for humans, especially in hypoxic environments where it can cause harm. Therefore, oxygen sensors are particularly important. Oxygen sensors are used in underground corridors to check the concentration of oxygen in the air to determine if they are in a comfortable environment and provide feedback so that construction workers can be in a safe oxygen environment. In hypoxic environments, different oxygen concentrations can cause different hazards, as shown in the table below.

If one is in a state of oxygen enrichment, it can also pose certain risks to human health, including:

1. Oxygen poisoning

When the oxygen content in the inhaled air is too high, excessive oxygen free radicals will be produced in the body, which will attack various biomolecules inside the cells, causing symptoms such as coughing, nausea and vomiting, dizziness, blurred vision, etc. In severe cases, convulsions, coma, and even death may occur.

2. Inhibition of respiratory center

The human respiratory center has a certain sensitivity to the concentration of carbon dioxide in the blood. In an oxygen rich environment, excessive carbon dioxide excretion can cause the concentration of carbon dioxide in the blood to be too low, thereby inhibiting the respiratory center and leading to shallow, slow, and even respiratory pauses.

3. Other effects

Long term exposure to oxygen rich environments may also affect the body's immune system, endocrine system, and lead to functional disorders. For example, it may alter the activity of immune cells and affect the body's immune defense function; The impact on the endocrine system may lead to hormonal imbalance, which in turn affects the normal metabolism and physiological functions of the body.

Conclusion

The human body's demand for oxygen has a relatively stable range, and whether in a state of hypoxia or oxygen enrichment, it can disrupt the balance of the body and pose a threat to health. For the detection of oxygen concentration, the AG-4 module can be used in conjunction with the Alphasense A-series electrochemical oxygen sensor for reliable pre calibrated oxygen concentration measurement. Its diameter is 20 millimeters, making it very suitable for portable gas detectors. Its high precision is crucial for safety, medical, air quality assessment, and oxygen level monitoring in industrial processes. The main features include high performance, no leakage, digital output: UART/TTL/RS232, pre calibrated before leaving the factory; The LF series is a lead-free oxygen sensor that complies with ROSH certification. The following figure shows the specific product model selection table.