采用双喷嘴静电纺丝技术制备了SnO2/In2O3复合纳米纤维,涂敷于带有金电极的氧化铝陶瓷管表面形成敏感薄膜,设计了一种新型薄膜型甲醛传感器。采用X射线衍射仪、热场发射扫描电子显微镜、O2-程序升温脱附仪和X-射线光电子能谱(XPS)仪,表征了SnO2/In2O3纳米纤维的相组成和微观形貌,分析了敏感薄膜成分配比对甲醛吸附强度与电化学的影响机理。在气体传感器静态测试系统上,采用XEDWS-60A型气敏元件分析仪测试了甲醛传感器敏感特性、温度特性、湿度特性、动态响应、抗干扰和稳定性。结果表明,以S50纳米纤维为敏感薄膜(膜厚为240nm)的甲醛传感器,在温度为500℃,甲醛浓度为0.5~50mg/L时,传感器线性度和灵敏度最大值分别为96.8%和97.5%,承受的温度上限为1000℃,动态响应和恢复时间分别为23和12s。此传感器对CO、NO。甲苯、菲、丙酮和甲醇等气体具有良好的抗干扰性能。在汽车上连续使用12个月后,响应衰减了5.5%,响应正常时间为6.4个月。
SnO2-In2O3 composite nanofibers of formaldehyde sensor were prepared by the double jets electrospinning method. A new film-type formaldehyde sensor was designed with SnO2-In2O3 composite nanofibers transferred onto an alumina ceramic tube with Au electrodes. The crystalline phase and microstructure of SnO2-In2O3 composite nanofibers were displayed using X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM), formaldehyde adsorption intensity and electrochemical mechanism of SnO2-In2O3 composite nanofibers were analyzed by oxygen temperature programmed desorption (O2-TPD) and X-ray photoelectron spectroscopy (XPS). These characteristic tests of formaldehyde sensor were carried out on the traits of sensitive performance, temperature, relative humidity, dynamic response, interference and stability by the XEDWS-60A type muhifunction analyzer in gas sensor static test system, the results demonstrated that formaldehyde sensor based on S50 composite nanofibers with 240 nm sensitive film thickness, when the operating temperature was 500 ℃ and formaldehyde concentration was increased from 0.5 to 50 mg/L, the best linearity and sensitivity of formaldehyde sensor were 96.8% and 97.5% respectively, and its high temperature level was 1000 ℃, the dynamic response time and recover time of formaldehyde sensor were 23 and 12 s, respectively. This kind of sensor showed good anti-disturbance to these gases, such as CO, NOx, toluene, phenanthrene, acetone, and methanol. The response value of formaldehyde sensor was attenuated about 5. 5%, when formaldehyde sensor was applied continually on the automobile about 12 months, and its normal time was 6.4 months.