Nano-gas sensitive material specific surface area analysis - Database & Sql Blog Articles

With the development of science and technology, the detection and monitoring of various gases, especially flammable gases and toxic gases, has become an urgent problem to be solved in the fields of industry, civil, national defense and transportation. The research of nano gas sensing materials plays an irreplaceable role in improving the sensitivity, selectivity and long-term stability of gas sensing materials, as well as how to reduce the working temperature and shorten the corresponding temperature and time.
At present, the detection of various gases at home and abroad is mainly for hydrogen, hydrogen sulfide, hydrocarbons, nitrogen oxides, ammonia, ethanol, liquefied petroleum gas (LPG), pipeline gas and other reducing gases and toxic gases. The more widely used gas sensing materials are mainly metal oxides such as SnO2, ZnO, SiO2, TiO2, Fe2O3, and WO3, and the composite oxide is also widely used as a solid electrolyte. Since conventional gas sensors such as SnO2 have high power consumption, low sensitivity, and poor selectivity, people have been trying to explore new methods to solve these problems.
Due to the small size of the nanocrystals, the electron energy levels near the Fermi level of the metal change from quasi-continuous to discrete energy levels, and the energy gap becomes wider. The special quantum size effect, surface effect and small size effect make nanomaterials Special properties not found in many bulk materials. Gas-sensitive materials such as nano-SnO2 have large specific surface and high activity and sensitivity. Their components have long life, high sensitivity and low cost, and have been at the center of metal oxide semiconductor resistive gas sensor research. In research and application, it is found that the purity and grain size of gas-sensitive materials such as SnO2 directly affect the gas-sensing properties of the materials. The particle shape, uniformity and stability of SnO2 powders directly affect the gas produced in the future. Important parameters such as sensitivity, power consumption, selectivity, response recovery characteristics and stability of the sensitive components.
Since the gas sensing mechanism of gas sensing materials such as tin oxide is surface controlled, the sensitivity of the gas is related to the specific surface area of ​​the material. Generally, the larger the specific surface area, the higher the gas sensitivity. The specific surface area is the surface area per gram of solid material in m2/g; the national standard for specific surface area testers is the BET multi-point method based on BET theory (GB/T 19587-2004). The main point of the specific surface area measured by the nitrogen adsorption BET multi-point method is: in the range of 5-30% nitrogen partial pressure, the adsorption amount of the adsorbent (the powder to be tested) to nitrogen is measured at different partial pressure points of nitrogen, and adsorption is made. The isotherm, the specific surface area of ​​the adsorbent can be calculated by the BET formula to determine the saturated adsorption amount of the monolayer when the surface of the adsorbent is covered with nitrogen molecules to cover the monolayer.
The 3H-2000BET-A specific surface area measuring instrument of Bestech Instrument Technology (Beijing) Co., Ltd. is a high-precision analytical instrument based on the national specific surface test standard. It has many domestic leading technologies; The purging process function requires a purge process between different nitrogen partial pressure points of the chromatographic specific surface test, which makes the purging process between different nitrogen partial pressure points more convenient and efficient, and reduces the accuracy of continuous testing. Impact; the only program-controlled wind-heat assisting device in China, which guarantees sharp and rapid desorption peak and reduces background error after full automation; the only chromatographic concentration detection system in China makes the nitrogen partial pressure detection accuracy increase relative to the flow method 10 times; six-way valve injector program control, the only domestic quantitative tube program-controlled switching function; the only domestic particle size report and other functions; the instrument parameter software display, at the same time, the large-screen LCD hardware display on the instrument, so that the instrument working state parameters At a glance, the operation is more reliable; and liquid nitrogen temperature monitoring, detector gas shutoff protection, detector thermostat, heavy The sound prompt of the link makes the 3H-2000BET-A surface surface instrument achieve and surpass the performance of similar instruments in foreign countries in terms of test accuracy, stability and safety, and ease of operation. The 3H-2000 series surface surface meter has a large number of customers in China. A well-known brand than the surface sensor.
The Besderby surface meter adopts fully automatic operation, is easy to learn, stable in instrument performance, accurate and fast in testing. It is deeply loved and praised by teachers, researchers and technicians in universities. It can also provide free samples for customers and the number of samples. More than 10,000 times, the experience of testing various materials has broken the monopoly of foreign surface meters, established our excellent national brand, and the products are affordable, and can be widely popularized and promoted.