Study On Several Metal Oxide Loaded With Rambutan-like Al₂O₃ Modified QCM Gas Sensors

QCM(Quartz Crystal Microbalance),also called quartz crystal microbalance,is a kind of quality gas sensor.Its advantages are low cost,high sensitivity,simple operation and real-time on-line detection.However,the sensor started late and developed slowly,which led to the lack of deep understanding of its mechanism and lack of research on the expansion of the gas sensor.In this paper,the rambutan-like Al2O3 has been successfully prepared by a composite soft template composed of macromolecule surfactant PEG4000 and organic compound DL-aspartic acid Based on the combination of high specific surface area of alumina and metal oxide(In2O3,ZrO2,CeO2)with good gas sensitivity,the QCM gas sensor of rambutan-like alumina composite film was prepared.The alumina composites prepared in this paper are characterized and analyzed by SEM?TEM?XRD?XPS?EDS?BET and so on.The main contents of this paper are as follows:1.Using surfactant PEG4000 and organic small molecule DL-aspartic acid as composite soft membrane plate,AlOOH with high specific surface area was successfully prepared by reflux method and urea as precipitator.adding In(NO3)3 solution with different molar ratio and appropriate amount of urea,refluxing at 100? for 2 h,washing,calcining at 450? for 3 h,a series of Al2O3/In2O3 composites were obtained as sensitive materials for QCM gas sensors.Preparation of 100 ppm H2 as gas to be tested.The results showed that the response value of the sensitive material with 20%In3+loading to H2 was 600 Hz,a good linear relationship was maintained,the sensitivity of the sensor is up to 6.26 Hz/ppm,and after a month of testing,the sensor shows good stability.2.A composite soft template was composed of surfactant PEG4000 and organic small molecule DL-aspartic acid.A certain amount of Al(NO3)3 solution and different proportion of ZrCl4 solution were added.Urea was used as precipitator and coprecipitation method was used.A series of rambutan-like AlOOH/Zr(OH)4 composites were prepared successfully.After washing and calcining at 600?,Al2O3/ZrO2 composites were obtained as gas sensing materials.100 ppm NH3 was prepared as the gas to be measured.The results showed that the response value of the sensitive material with 1%Zr4+ dopant to NH3 was 705 Hz,and the linear relationship was good,the sensitivity of the sensor is up to 7.11 Hz/ppm,and after one month's test,the sensor shows good stability.Using surfactant PEG4000 and organic small molecule DL-aspartic acid as composite soft membrane plate,AlOOH with high specific surface area was successfully prepared by reflux method and urea as precipitator.Adding ZrCl4 solution with different molar ratio and appropriate amount of urea,refluxing at 100? for 2 h,washing,calcining at 600? for 3 h,A series of Al2O3/ZrO2 composites were obtained as sensitive materials for QCM gas sensors.Preparation of 100 ppm NH3 as gas to be tested.The results showed that the response value of the sensitive material with 30%Zr4+loading to NH3 was 685 Hz,a good linear relationship was maintained,the sensitivity of the sensor is up to 6.90 Hz/ppm,and after a month of testing,the sensor shows good stability.3.Using surfactant PEG4000 and organic small molecule DL-aspartic acid as composite soft membrane plate,AlOOH with high specific surface area was successfully prepared by reflux method and urea as precipitator.Adding different mole ratio of Ce(NO3)3 solution and appropriate amount of urea,stiring for 1 h,transfering to the reactor lining,hydrothermaling at 200? for 3 h,washing,calcining at 450?,Al2O3/CeO2 nanocomposites have been successfully fabricated as gas sensor materials.100 ppm HC1 was prepared as the gas to be measured.The results showed that the response value of the sensitive material with 15%Ce4+loading to HCl was 886 Hz,a good linear relationship was maintained,the sensitivity of the sensor is up to 8.90 Hz/ppm,and after a month of testing,the sensor shows good stability.