What Is a Hydrogen Sensor?
The hydrogen sensor is very sensitive to hydrogen at room temperature and has good selectivity. It can be used as a sensor to detect the hydrogen concentration in the environment. Due to the safety requirements in production and life, a fast and sensitive hydrogen sensor is necessary and can be timely Avoid the possibility of explosion.
Hydrogen sensor
- Chinese name
- Hydrogen sensor
- Foreign name
- hydrogen sensor
- Steel mill
- Battery system
- Transformer maintenance
- Hydrogen alarm
- Detection of hydrogen
- The hydrogen sensor is very sensitive to hydrogen at room temperature and has good selectivity. It can be used as a sensor to detect the hydrogen concentration in the environment. Due to the safety requirements in production and life, a fast and sensitive hydrogen sensor is necessary and can be timely Avoid the possibility of explosion.
- Hydrogen is known as three major new energy sources together with solar energy and nuclear energy due to its advantages such as high combustion efficiency and no pollution of products. As a new energy source, hydrogen has been widely used in aviation, power, and other fields.At the same time, hydrogen is a reducing gas and carrier gas, which is extremely important in chemical, electronics, medical, and metal smelting, especially in the military and defense fields. Value. But the hydrogen molecule is very small, and it is easy to leak during the production, storage, transportation and use. Because hydrogen is not good for breathing, it is colorless and odorless and cannot be detected by the human nose. The ignition point is only 585 , and the content of air is 4% In the range of ~ 75%, an explosion will occur in the presence of an open flame. Therefore, in the use of hydrogen, a hydrogen sensor must be used to detect the hydrogen content in the environment and monitor its leakage.
- 1.Semiconductor sensors
- Take resistive semiconductor sensors as examples: mainly use sno2, zno, wo3 and other metal oxides as gas-sensitive materials. For example, domestic qm series hydrogen sensors use sno2 as hydrogen-sensitive materials, so they are also called metal oxide semiconductor hydrogen sensors. The working principle is that when hydrogen is adsorbed, the hydrogen releases electrons as donors and combines with oxygen ions in the chemisorption layer, so the carrier concentration changes, and the change value has a certain function relationship with the hydrogen volume fraction.
- 2.Pyroelectric sensor
- First, a layer of thermoelectric material is deposited on the substrate, and then a layer of catalytic metal, such as pt, pd, is deposited on a part of the surface of the thermoelectric material.Finally, the catalytic metal layer and the thermoelectric thin film layer (there is no catalytic metal on the surface) ) Lead out the electrode, that is to obtain the simplest thermoelectric hydrogen sensing element. When this sensitive element is exposed to a hydrogen-containing environment under the action of a catalytic metal, the hydrogen reacts with oxygen to generate water vapor and emit heat.Therefore, the end where the catalytic metal is deposited is high in temperature and is the hot end, and the end without the catalytic metal The temperature is low and it is the cold end. Due to the thermoelectric power generation effect of the thermoelectric material (seebeck effect), the temperature difference between this hot end and the cold end is converted into a temperature difference potential, which is output as an electrical signal to achieve the detection of hydrogen.
- Fiber optic sensor
- Since many solid-state hydrogen sensors use electrical signals, a common drawback is that electric sparks may be generated, which is a great safety hazard for environments with high hydrogen volume fractions. The optical fiber sensor uses optical signals, so it is suitable for explosive and hazardous environments.
- At present, the selectivity, safety, stability, sensitivity, and weak output signal of hydrogen sensors have been solved to varying degrees. Achieving the normal temperature operation of the hydrogen sensor will not only improve the safety of the hydrogen sensor, but also reduce energy consumption, which will be the focus of future research work. There are three ways to achieve the normal temperature work of hydrogen sensors: 1) the development of fiber-optic hydrogen sensors, but the problems of weak output signals, short service life, and high costs must be solved; 2) the preparation of nano-scale hydrogen-sensitive materials, due to hydrogen The response of sensitive materials to hydrogen is basically a surface effect, and nanomaterials have a large specific surface area, which increases the surface area of contact response, and the particle size of nanomaterials is small, shortening the response time, and improving the response. Performance; 3) Actively develop new hydrogen-sensitive materials.