基于介孔燃烧催化材料的气敏传感器的研究

Study of gas sensor based on mesoporous catalytic combustion materials

用模板法制备了Pd/Al_2O_3催化剂材料,以异丙醇铝、异丙醇、水为原料,通过离子交换法将Pd担载到Al_2O_3上。对烧结温度对比表面积和载体材料的晶体结构的影响进行了研究,得到结论如下:对Al_2O_3的热分析中得出800℃是煅烧凝胶Al_2O_3的最佳温度。通过水与异丙醇不同比例的Al_2O_3的XRD分析表明,800℃烧结后的粉体主要是Al_2O_3的晶体结构。经离子交换方法 Al_2O_3载体中承载Pd后的XRD分析显示,主要是Pd和Al_2O_3混合结构。透射电镜下氧化铝呈线条状,Pd呈颗粒状,加入了Pd以后在电镜下观察有团聚现象出现。吸附曲线和孔径分布图表明,水与异丙醇铝配比4:1时比表面积BET值最大为332.0582m^2/g,孔径分布为20nm,载体Al_2O_3加入了催化材料Pd之后配比在3:1时比表面积最大,为321.3280m^2/g,孔径分布10nm。在灵敏度测试中,水与异丙醇铝的配比为3:1时,灵敏度高,可以长期工作,寿命长。

Pd/Al2O3 catalyst material is prepared at first by template method with aluminium isopropoxide, isopropanol and water as raw materials, and Pd is supported on Al2O3 by ion exchange method. The effect of sintering temperature on the specific surface area and crystal structure of the carrier material are investigated. The conclusions are got as follows： The thermal analysis of Al2O3show that the optimum sintering temperature of gel Al2O3 is 800℃. The XRD analysis of Al2O3 with different ratio of water and isopropanol indicate that the main structure of sample after 800℃ sintering is crystal structure of Al2O3 The XRD analysis of Pd-supported Al2O3 indicate that the structure of sample is composite structure of Pd and Al2O3. Under the transmission electron microscope, the alumina is in linear shape, the Pd is granular, and the aggregation phenomenon is observed after Pd is added. Adsorption curve and aperture distribution diagram indicate that when the radio of water and aluminium isopropoxide is 4：1, the BET of the specific surface area is maximum with 332.0582 m2/g and the aperture distribution is 20nm. When the ratio of carrier Al2O3 and catalyst Pd is 3：1, the specific surface area is maximum with 321.3280m-2/g, and aperture distribution is 10nm. In the sensitivity tests, when the radio of water and aluminum isopropoxide is 3：1, the sensitive cell has high sensitivity and long service life and can work for a long time.