title: Room-temperature NH3 gas sensors based on Ag-doped γ-Fe2O3/SiO2 composite films with sub-ppm detection ability.
abstract: In this report, NH3 gas sensors based on Ag-doped γ-Fe2O3/SiO2 composite films are investigated. The composite films were prepared with a sol-gel process, and the films' electrical resistance responded to the change of NH3 concentration in the environment. The SEM and AFM investigations showed that the films had a porous structure, and the XRD investigation indicated that the size of Ag particles changed with the modification of Ag loading content. Through a comparative gas sensing study among the Ag-doped composite films, undoped composite film, γ-Fe2O3 film, and SiO2 film, the Ag-doped composite films were found to be much more sensitive than the sensors based on the undoped composite film and γ-Fe2O3 film at room temperature, indicating the significant influences of the SiO2 and Ag on the sensing property. Moreover, the sensor based on Ag-doped (4%) γ-Fe2O3/SiO2 composite film was able to detect the NH3 gas at ppb level. Conversely, the responses of the sensor to other test gases (C2H5OH, CO, H2, CH4 and H2S) were all markedly low, suggesting excellent selectivity.
authors.affiliation: Institute of Fundamental and Frontier Sciences and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Institute of Fundamental and Frontier Sciences and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Fundamental and Frontier Sciences and School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China. Electronic address: xtzu@uestc.edu.cn.
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Zu
authors.affiliation: Sichuan Institute of Piezoelectric and Acousto-optic Technology, Chongqing 400060, China.
authors.forename: Jinyi
authors.initials: J
authors.lastname: Ma
authors.affiliation: Sichuan Institute of Piezoelectric and Acousto-optic Technology, Chongqing 400060, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: Sichuan Institute of Piezoelectric and Acousto-optic Technology, Chongqing 400060, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Sichuan Institute of Piezoelectric and Acousto-optic Technology, Chongqing 400060, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Du
authors.affiliation: Ingram School of Engineering and MSEC, Texas State University, San Marcos, Texas 78666 USA. Electronic address: qingkai.yu@txstate.edu.
authors.forename: Qingkai
authors.initials: Q
authors.lastname: Yu
mesh_terms: D000641:Ammonia / Q000032:analysis*; D005296:Ferrous Compounds / Q000737:chemistry*; D005740:Gases / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D005296:Ferrous Compounds; D005740:Gases; D012834:Silver; D012822:Silicon Dioxide; D000641:Ammonia; C034236:ferrous oxide
keywords: Ag; NH(3); Sensor; SiO; γ-Fe(2)O(3)