Study On Detection Characteristic Of Gas Sensing And Gas Sensor Of Nanocrystalline Metal Oxide Semiconductor

The gas dissolved in transformer oil on-ine monitoring has become an importantmeans to achieve the transformer condition maintenance, but the critical is thatdetection technology of sensor for on-line monitoring.However gas sensor of metaloxide semiconductor can be applied in on-line monitoring.Gas sensors applied ondevices of gas dissolved in transformer oil on-line monitoring at home and abroadcontain a lot of problems such as low sensitivity, large dispersion of data, short life,poor stability of long-termoperation, all of these shortages severely restrict theapplication and development of the technology. So it is very important value andsignificance to in-depth study on gas sensor of metal oxide semiconductor.Through the analysis of the characteristics of metal oxide semiconductor sensorand sensing mechanism, and the combination of nanotechnology to influenceperformance of gas sensor, we put forward preparation of doped amout of5%Pd, Pt,Rh, Ir SnO₂and undoped SnO₂ultrafine powder by Sel-gel, By XRD and SEMcharacterization shows that: Prepared powders are nanoscale particles, sphericalpowders, good dispersion and uniform particle size.We studied gas detection characteristics of the elements of SnO₂that made bysintered ceramics process to gases dissolved in transformer oil such as CH₄, C₂H₆,C₂H₄, C₂H₂, H₂, CO. The results show that gas detection characteristics of dopingelements are much better that of undoping elements. In which doping element showedmaximum sensitivity for methane at4V heating voltage, acetylene and ethyleneshowed maximum sensitivity at4.5V, only at5V did ethane, hydrogen and carbonmonoxide, the undoped components only at5V showed slightly better sensitivity forsix gases, but it is very poor under the other heating voltages. Doping element in thedifferent heating voltage showed good selectivity for the six gases, which is the highestfor methane at4V, and the best for acetylene, ethylene and ethane at4.5V, but it is notgood for six gases at5V, however the undoped components did not show a certainregularity in the selectivity. The linearity of doping element under the three heatingvoltages was generally good, but the linearity performance of undoped component wasnot stable and quite different. The response-recovery time of doped element wassignificantly shorter than the undoped components. The resolution of dopingelement,in addition to methane, ethane, ethylene slightly higher than the standard value, the minimum detection value of the remaining three gases are below thestandard value, reflecting a better resolution, the resolution of undoping of componentwas poor.Repeatability and long-term stability of the doping element also havesignificantly improved and enhanced than that of undoped component.We analyzed detection characteristics of gas sensors of nanocrystalline combinedthe mechanism of gas sensing response, while we calculated and analyzed the energyorbit of molecular by Gaussian10software, and qualitatively explaned the gasdetection characteristics of the sensors from the perspective of quantum of molecular.