Research On The Preparation And Characteristics Of Highly Sensitive ZnO Based Thick Film Acetone Gas Sensors

ZnO gas sensing materials have excellent performance,low cost and environmental friendliness,and become the main gas sensing materials in acetone gas sensors.At present,ZnO-based acetone gas sensor has become a research hotspot at home and abroad.With the deepening of research,its gas sensitivity characteristics are gradually improved,but there are still shortcomings such as poor selectivity,high working temperature,poor stability and high detection concentration limit,which limits its Industrial application.In the next few years,improving the selectivity and stability of ZnO-based acetone gas sensor,reducing its working temperature and lower limit of detection concentration,has become the key research direction to improve the gas sensitivity of ZnO-based acetone gas sensor.In this paper,sol-gel method was used to prepare ZnO powder with Co₃O₄ doping amounts of 0wt%,2.13wt%,4.13wt%,and 6.13wt%,respectively,which were filtered,annealed,and ground.In order to study the surface morphology,structure,composition and band characteristics of the materials,Co₃O₄ doped ZnO samples were tested and characterized by XRD,XPS,SEM,EDS and UV-vis spectroscopy.The optimal process conditions for the preparation of ZnO-based gas sensing materials were proposed by systematic comparison experiments.The gas content of Co₃O₄ and the annealing temperature were studied for the gas of Co₃O₄-ZnO thick film acetone gas sensor.The effect of sensitivity;The effect of photoexcitation on the gas sensing properties of Co₃O₄-ZnO nanomaterials acetone was studied by UV-visible excitation test;the effect of aging temperature and ambient humidity on the stability of Co₃O₄-ZnO thick film gas sensor was investigated by means of aging experiments;The gasification mechanism of the Co₃O₄-ZnO thick film acetone gas sensor is further analyzed by the combination of the mass spectrometry model and the UV-visible excitation theory.The experimental results show that: the optimal working temperature of 4.13wt% Co₃O₄-ZnO heterostructure nanomaterials is as low as 30?.At this operating temperature,the 4.13wt% Co₃O₄-ZnO element annealed at 700? has a sensitivity of 24.4 to 100 ppm acetone,3.7 times higher than undoped ZnO,and response and recovery times were also reduced from 16 and 7 seconds to 4 and 3 seconds,respectively.The incorporation of Co₃O₄ significantly enhances the sensitivity of the ZnO gas sensor and the selectivity to acetone,effectively reducing the operating temperature;Ultraviolet excitation has a significant effect on the gas sensitivity of the material.Under ultraviolet light,the sensitivity of the component to 100 ppm acetone is 50.1,which is about twice the gas response in dark conditions.Moreover,the sensitivity of the visible light to the material also has a significant effect.Under visible light,the sensitivity of the component to 100 ppm acetone is 37.2,which is about 1.5 times that of the gas under dark conditions.The doping of Co₃O₄ significantly improves the utilization of visible light;The component has an attenuation of only 2% after aging for 32 days at an aging temperature of 30? and a relative humidity of 88%RH.Suitable aging conditions can improve the stability of the Co₃O₄-ZnO thick film acetone gas sensor.The 700 ? annealing and 4.13wt% Co₃O₄ doping process used in the project effectively improved the sensitivity and selectivity of the ZnO-based thick film gas sensor to acetone gas,lowered the working temperature,and facilitated the detection of low-concentration acetone.