Research On The Gas Sensing And Humidity Sensing Properties Based On The Preparation Of ZnSnO₃ Nanomaterials

At present, the world has entered the era of information technology. The sensor as the main tool of obtaining information attaches great importance in the industry developed countries, and is widely used in industrial automation, agricultural natural disasters, medical diagnosis, environmental monitoring. Humidity sensor and gas sensor, as two important branches in sensing field, can transform the outside information of the humidity and atmosphere into the available signals, respectively. Sensitive material largely determines the characteristics of the wet sensor and gas sensor. As a perovskite type composite oxide, ZnSnO₃ has high electron mobility, high electrical conductivity. Nanomaterials based on ZnSnO₃ have attracted great attention in many fields such as optics, electricity, magnetism and catalyst. So far, the sensing property of ZnSnO₃ has aroused researcher’s concern and research.In this paper, Sb-doped ZnSnO₃ fine nanoparticles were synthesized via a dual-hydrolysis-assisted liquid precipitation reaction and subsequent hydrothermal procedure. The nanoparticles were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and UV-visible spectrophotometry. The results demonstrated that ZnSnO₃ nanocubes evolved into Sb-doped ZnSnO₃ nanoparticles with doping by Sb. In this evolution, ZnSnO₃ nanoparticles have smaller particle size and larger specific surface area, which means that they have good performances of their application in humidity sensing and gas sensing.At room temperature, the resistance of the humidity sensors based on Sb-doped ZnSnO₃ at 30% relative humidity （RH） was 130 times greater than that in air with 85% RH. The response and recovery times were 7.5 s and 33.6 s, respectively, when the sensors were switched between 30% and 85% RH. The gas-sensing properties research of Sb-doped ZnSnO₃ nanoparticles for CO, H2, SO2, CH3CH2OH gas was operated under the different working temperature. Under the best working temperature 300℃, gas sensitive element react with 100 ppm CH3CH2OH gas, and the response and recovery times respectively were 3 s and 33.2 s, and the sensitivity was 12.9. The doping of Sb improved the recovering response speed and sensitivity of ZnSnO₃ nanomaterials. These results suggest that doping is an effective way to change structure of material, and provides a good way to improve the humidity sensing properties and gas sensing characteristics.