Fluorinated TiO<sub>2</sub> Hollow Spheres for Detecting Formaldehyde under UV Irradiation
Jianwei Zhang,
Baoyu Huang,
Xinlei Li,
Chao Yang,
Wenzhuo Zhao,
Xiuhua Xie,
Nan Wang,
Xiaogan Li
Affiliations
Jianwei Zhang
School of Artificial Intelligence, Dalian University of Technology, Dalian 116024, China
Baoyu Huang
School of Integrated Circuits, Dalian University of Technology, Dalian 116024, China
Xinlei Li
School of Integrated Circuits, Dalian University of Technology, Dalian 116024, China
Chao Yang
Beijing Research Institute of Telemetry, Beijing 100076, China
Wenzhuo Zhao
School of Integrated Circuits, Dalian University of Technology, Dalian 116024, China
Xiuhua Xie
State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033, China
Nan Wang
School of Integrated Circuits, Dalian University of Technology, Dalian 116024, China
Xiaogan Li
School of Integrated Circuits, Dalian University of Technology, Dalian 116024, China
The fluorinated titanium dioxide (F-TiO2) hollow spheres with varying F to Ti molar ratios were prepared by a simple one-step hydrothermal method followed by thermal processing. The diameter of the F-TiO2-0.3 hollow spheres with a nominal ratio of F:Ti = 0.3:1 was about 200–400 nm. Compared with the sensor based on pristine TiO2 sensing materials, the F-TiO2-0.3 sensor displayed an enhanced sensing performance toward gaseous formaldehyde (HCHO) vapor at room temperature under ultraviolet (UV) light irradiation. The F-TiO2-0.3 sensor demonstrated an approximately 18-fold enhanced response (1.56) compared to the pristine TiO2 sensor (0.085). The response and recovery times of the F-TiO2-0.3 sensor to 10 ppm HCHO were about 56 s and 64 s, respectively, and a limit-of-detection value of 0.5 ppm HCHO was estimated. The F-TiO2-0.3 sensor also demonstrated good repeatability and selectivity to HCHO gas under UV light irradiation. The outstanding HCHO gas-sensing properties of the F-TiO2-0.3 sensor were related to the following factors: the excitation effect caused by the UV light facilitated surface chemical reactions with analyte gas species; the hollow sphere structure provided sufficient active sites; and the surface fluoride (≡Ti−F) created additional chemisorption sites on the surface of the TiO2 material.