TiO_2/Ag_2O纳米材料的制备及其对甲醛的气敏性能

Preparation and Gas Sensing Properties to Formaldehyde of TiO_2/Ag_2O Nanocrystalline

采用溶胶-凝胶法制备了掺杂Ag的TiO2纳米晶粉体.用XRD、TEM和BET方法对纳米晶的晶型﹑晶粒大小和表面性能进行了表征.分析结果显示,相同条件下掺杂Ag的TiO2比纯TiO2纳米材料具有更大的比表面积.气敏性能测试结果表明,掺杂Ag的TiO2传感器对甲醛有较好的灵敏度和更高的选择性.当焙烧温度为500℃,掺杂Ag的摩尔比为5%(n(AgNO3)/n(Ti(OC4H9)4)=5%)时,TiO2对甲醛气体敏感性能最好.在最佳工作电流124mA下,该元件对10"L·L-1HCHO的灵敏度S接近4,它的响应时间不超过1s,恢复时间为9s.

Pure and Ag-doped TiO2 powders were prepared by sol-gel method. The crystal structure, particle size and surface properties of the samples were characterized by means of X-ray diffraction（XRD）, transmissionelectron microscopy（TEM） and Brunaner-Emmett-Teller（BET） surface areas. The results revealed that the Ag dopant increased the specific surface area of TiO2 powders. The sensitive properties of the samples were also investigated. It was found that the doped sensor had a better sensitivity and higher selectivity to HCHO than the pure one. The sensitivity of the sensor, which was prepared with 5% Ag-doped TiO2 calcined at 500 ℃, was the highest. With the optimum working current of 124 mA, the sensitivity of the sensor was approximate to 4 at its detection limit of 10 μL·L^-1, its recovery time was 9 s whereas response time was no more than I s.