基于CeO2-Co3O4纳米纤维的催化发光式甲醛传感器研究

采用双喷嘴静电纺丝法制备了CeO2-Co3 O4纳米纤维,将制备的CeO2-Co3 O4纳米纤维均匀涂覆于 ω型加热线圈表面形成催化发光薄膜,设计了一种新型催化发光甲醛传感器.采用X射线衍射仪、 扫描电子显微镜、 全自动程序化学吸附仪和X-射线光电子能谱仪,表征了Co3 O4-CeO2纳米纤维的相组成和微观形貌,讨论了甲醛在CeO2-Co3 O4催化剂表面的电化学特性和催化发光机理.在优化条件下,即波长500 nm、 温度550℃ 、 载气流速0.2 L/min,甲醛传感器件(Ce30)催化发光强度与甲醛浓度在1.2~50μg/m3范围内有良好的线性关系,灵敏度为40.04 a.u./(μg/m3),检出限为1.2μg/m3,动态响应和恢复时间分别为2.4和3.5 s.此传感器可用于汽车尾气中甲醛浓度检测,相对误差范围为0.4%~1.1%,相对标准偏差RSD<3%(n=6).

Research on Cataluminescence Type Formaldehyde Sensor Based on CeO2-Co3 O4 Nanofibers

CeO2-Co3 O4 composite nanofibers were prepared by the double jets electrospinning method. The nanofibers were then deposited onto the surface of a ω-type heating coil as cataluminescence material to prepare a new cataluminescence ( CTL ) type formaldehyde gas sensor. The crystalline phase and microstructure of CeO2-Co3 O4 composite nanofibers were characterized by X-ray diffraction ( XRD) and scanning electron microscope (SEM), and the cataluminescence mechanism and electrochemical characteristic of formaldehyde on the surface of CeO2-Co3 O4 nanofibers were analyzed by H2 temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). Under the optimal conditions (500 nm of wavelength, 0. 2 L/ min of flow rate and 550℃), there was a good relationship between the CTL intensity of this formaldehyde gas sensor (Ce30) and formaldehyde concentration in the range of 1. 2 -50 μg / m3 , the sensitivity was 40. 04 a. u. / (μg / m3 ), the detection limit was 1. 2 μg / m3 , the dynamic response time and recover time of formaldehyde gas were 2. 4 s and 3. 5 s, respectively. The formaldehyde sensor was successfully applied to the determination of formaldehyde in the automotive exhaust, with relative errors of 0. 39% -1. 07% and relative standard deviations of less than 3% .