Research On Preparation Method Of Triethylamine Gas Sensor Based On Micro-arc Oxidation And Experimental Verification

Triethylamine is an important industrial raw material.Long-term inhalation will strongly stimulate the human skin,mucous membranes and nervous system.At present,conductive polymer sensors,catalytic luminescence gas sensors and metal oxide semiconductor gas sensors have been used for the detection of triethylamine.Among them,metal oxide semiconductor gas sensors have become the mainstream of current triethylamine sensors due to their advantages of high sensitivity,fast response speed,small size,and low cost.However,with the continuous improvement of application requirements,the performance requirements for triethylamine sensors are also continuously improved.Problems such as low sensitivity,slow response,poor selectivity and stability restrict the development and application of triethylamine semiconductor sensors.Therefore,how to improve the detection performance of triethylamine semiconductor gas sensors is an urgent problem to be solved.In this paper,micro-arc oxidation technology is used to control the preparation of titanium dioxide(TiO2)film layer to achieve efficient detection of triethylamine,improve the comprehensive performance of micro-arc oxidation gas sensors,and provide technology for the preparation of metal oxide semiconductor gas sensors support.This paper will carry out research from the following aspects:Firstly,according to the gas-sensing mechanism of semiconductor metal oxide materials and triethylamine,the basic conditions and influencing factors of micro-arc TiO2 film to triethylamine gas were studied through the performance regulation method of semiconductor metal oxide gas-sensing materials;Furthermore,the influence of the structure and gas diffusion effect on the surface of the senor was studied.The adsorption and desorption processes of oxygen and triethylamine gas on the surface of the micro-arc oxidation film were analyzed,and the redox reaction in the gas sensor of micro-arc oxidation was discussed in detail.Theoretical studies have found that the structure of the membrane layer has a significant impact on the response of the sensor.Increasing the pore size within a certain range is conducive to improving the gas sensing performance of the membrane layer.Doping with other metal elements is conducive to improving the microstructure of the membrane layer and improving the performance of gas sensors.Then,according to the process requirements of micro-arc oxidation,an experimental system was built to carry out process experimental research,and the preparation of microarc oxidation film layer was carried out;the structure and composition of micro-arc oxidation film layer were characterized by SEM,EDS,XRD,XPS and BET methods;The vacuum ion sputtering method was used to make interdigital electrodes on the surface of the film layer to complete the production of micro-arc oxidation gas sensing elements;a performance testing platform for gas sensing elements was built,and the static gas distribution method was used to realize the triethylamine gas sensing of the micro-arc oxidation gas sensing film layer.Performance verification.Then,the influence of micro-arc oxidation process parameters,doping method and electrode structure parameters on the gas sensing characteristics of triethylamine gas sensor morphological structure was studied.Carry out single-factor experiments to study the influence of process parameters(electrolyte system and concentration,current density,oxidation time and pulse width)on the morphology and performance of the film;study the effect of electrolyte doping and compound process doping on the micro-arc oxidation film The effect of layer gas sensing performance;design electrode structure to change electrode parameters,and study the effect of electrode gap on the performance of micro-arc oxidation gas sensing element.The experimental results show that the gas-sensing film layer prepared by the electrolyte system of Na3PO4 and NaOH has a higher response to triethylamine;excessive current density is not conducive to the adsorption and desorption of triethylamine.When the oxidation time is too long,the surface porosity of the film layer will decrease,and the gas sensing performance will be poor;if the oxidation time is too short,the film layer will not grow completely,and the gas sensing performance will be poor;if the pulse width is too low or too high,the gas sensing performance of the film will be caused poor.The micro-arc oxidation electrolyte doping can greatly improve the film structure and improve the gas sensing performance of the film.The optimal doping concentration is 3g/L.The composite film prepared by the composite process has poor gas-sensing properties.The gas sensor has the highest performance when the electrode gap is 250μm.Finally,the process optimization and experimental verification of the gas sensor are carried out.The micro-arc oxidation process parameters were optimized by orthogonal test,and the gas-sensitive film layer prepared under the optimal process parameters was verified.Micro-arc oxidation gas-sensing films were prepared by doping different concentrations of Na2WO4 under the optimal parameter combination,and the gas-sensing properties of the films under the optimal doping amount were verified.The optimal process parameters,optimal doping amount and optimal electrode parameters are used to prepare the optimal gas sensor.The experimental verification results show that the optimal micro-arc oxidation gas sensor film has a porosity of 16.523%and a specific surface area of 17.9208 m2·g-1 is 2.5 times that of pure micro-arc TiO2 film.The sensitivity of the optimal gas sensor to 100ppm TEA is 14.7,which is twice as high as that of the pure micro-arc TiO2 film,and the response recovery time is 3s and 28s respectively,with good selectivity,fitting,repeatability and stability.