Study On The Preparation Of SnO₂ Hierarchical Nanostructures And Its Gas-sensitivity Properties

In this paper,the SnO₂ hierarchical structure was successfully synthesized by hydrothermal method,and the precious metal Ag particles were loaded on the surface.The above two materials are evenly coated on the interdigitated electrode as a sensitive layer to produce a gas sensor.And the gas-sensitive performance test of ethanol gas is carried out in the gas-sensitive test system built by the laboratory.The SnO₂ hierarchical structure was prepared by adjusting the hydrothermal reaction time and the amount of alkali source,and the surface structures and components were characterized.It was found that the SnO₂ hierarchical structure morphology prepared successfully when the hydrothermal reaction time was 12h and the Na OH was 2mmol was the most completely,the effects of annealing time and annealing temperature on the morphology and reunion degree of SnO₂ hierarchical structure were investigated.It was found that the surface structure of SnO₂ was the most complete when the annealing temperature was 500?and the annealing time was 2h.Noble metal Ag particles were loaded on the surface of SnO₂ hierarchical nanostructures,and the loading amount was 5.0 wt.%.The SnO₂ material and the Ag-SnO₂ material are dispersed in deionized water,coated with a substrate to prepare a gas sensor,and the above two gas sensors are tested by a gas-sensitive system.Gas sensing tests were carried out on three SnO₂ hierarchical structure with different annealing temperatures.The SnO₂ hierarchical structure gas sensor with an annealing temperature of 500?and an operating temperature of 300?had a sensitivity of 22.8 to 500ppm ethanol gas.The response and recovery time is 90s and 69s respectively.the 5.0 wt.%Ag-SnO₂ gas sensor was tested for ethanol gas sensitivity,and it was found that the Ag-SnO₂ gas sensor had an operating temperature of 250?,the response value of 500ppm of 51.1 toward ethanol gas,and the response-recovery time of 46s and 37 s respectively,with fast response speed,and good repeatability and stability.