The Modification Of Molecular Imprinting Ag-LaFeO₃ And The Study Of Its Acetone-sensing Properties

Acetone is the simplest ketone,as one of the most important industrial solvents,its chemical activity is high,relatively cheap and flammable.Furthermore,acetone is a metabolism product of animals and human body,and the content of acetone can reflect the health condition of the tested organism.So,timely and accurate detection of acetone gas is very important.Oxide semiconductor gas sensor has the advantages of high sensitivity,good stability,low cost,small size,easy to carry and so on.It has a widely applications and development potential in the field of gas detection.At present,binary metal oxide semiconductor was widely studied,which was used as sensing materials.But there is still a big gap between the performance and the practical application.In this paper,we prepared molecular imprinting technique Ag-LaFeO₃?MI-AL?as base material.The different morphology of materials was adjusted by template and modified by different carbon materials.The prepared samples were characterized by various advanced analysis and testing methods.The prepared gas sensing materials were made into ceramic tubular gas sensor and its gas sensing performance was studied systematically,and the main results obtained are as follows:?1?Research of different mopphology of MI-AL materialsAmong the different morphology of prepared materials based on MI-AL sol,the response of MI-AL fiber and MI-AL rod are low.However,the working temperature of gas sensor based on and MI-AL rod is 60?.The self-made carbon spheres were used as templates to prepare MI-AL sphere?MI-ALS?,and the influence of different template amounts on its gas sensing properties was also studied.When the carbon spheres quality is 30 wt%,the gas sensing properties of MI-ALS is the best.At the working temperature of 155?,the sensitivity of gas sensor to 5 ppm acetone is 23.3,the response and recovery time are 55 s and 60 s respectively,which shows a better selectivity.In a comprehensive view,the gas sensing properties of MI-ALS is the best.?2?Research of MWNTs modified MI-AL materialsIn order to elevate the gas sensing properties of gas sensor,the MI-AL was modified by MWNTs.The addition of MWNTs are 0.25 wt%,0.50 wt%,0.75 wt%,1.00 wt%and 1.25 wt%,respectively.When the addition of MWNTs is 0.75 wt%,the material shows the maximum sensitivity 59,and the working temperature is 86?.At the same working temperature,the response and recovery time are 58 s and 33 s,respectively,which shows a better selectivity.?3?Research of GO modified MI-AL materialsIn order to study the impact of different additions of GO to the properties of the materials on the gas sensitivity,the amounts of GO are 0.1 wt%,0.25 wt%,0.50 wt%,0.75 wt%,1.00 wt%and 1.25 wt%,respectively.When the addition of GO is 0.25 wt%,the material shows the best sensitivity to 5 ppm acetone,while the working temperature is 99?.and response and recovery time are 22 s and 24 s respectively.The sensitivity to other gases is below 8,which shows a better selectivity,The innovation of this paper is mainly embodied in the preparation of special shape of Ag-LaFeO₃ gas sensing materials and the modification of Ag-LaFeO₃ by GO and MWNTs.