Fabrication of flexible polyaniline@ZnO hollow sphere hybrid films for high-performance NH 3 sensors
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Fabrication of flexible polyaniline@ZnO hollow sphere hybrid films for high-performance NH3 sensors Tavakkol Tohidi1,*
, Somayeh Tohidi2, and Rahim Mohammad-Rezaei3
1
Northwest Research Complex, Radiation Applications Research School, Nuclear Science and Technology Research Institute, Bonab, Iran 2 Department of Condensed Matter Physics, Faculty of Physics, University of Tabriz, Imam St., 29 Bahman Blvd, Tabriz, Iran 3 Electrochemistry Research Laboratory, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
Received: 15 July 2020
ABSTRACT
Accepted: 6 September 2020
In this study, a simple inexpensive gas sensor, which uses polyaniline@ZnO hollow sphere hybrid films, is prepared with different mole percentages of ZnO hollow spheres (5–30 mol%) and combining hydrothermal and in-situ chemical oxidative polymerization methods. Polyaniline@ZnO hollow sphere hybrids are loaded on flexible polyethylene terephthalate substrates for rapid and selective detection of ammonia at room temperature. The morphology, structure, chemical functional group information and the specific surface area are, respectively, characterized by field emission-scanning electron microscopy, X-ray diffraction, Fourier transform infrared and N2 adsorption–desorption techniques. The best sensing performance is realized for the polyaniline@20 mol% ZnO hollow sphere hybrid sensor, which is exposed to 10 ppm ammonia at room temperature. Moreover, this sensor exhibits a low detection limit of 500 ppb, excellent selectivity and good response/recovery times (140/136 s). This good sensing performance can be attributed to the hollow structure of ZnO and the p–n heterojunction between the polyaniline and ZnO hollow spheres.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction Ammonia (NH3) is a toxic gas, which can cause serious damage to public and domestic safety. As reported by the United States Occupational Safety and Health Administration (OSHA), the exposure limit to NH3 in the workplace is 25 ppm over an 8 h period, and 35 ppm over 15 min [1]. Hence, it is imperative to develop an efficient NH3 sensor with
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https://doi.org/10.1007/s10854-020-04448-7
high sensitivity that can operate at room temperature with a low detection limit. Several studies on metal oxide semiconductors have investigated the development of NH3 gas sensors [2–4]. However, the high operating temperature of these materials and their poor selectivity restrict their practical applications [5]. In recent years, conducting polymers (polyaniline, polypyrrole, polythiophene) have attracted significant attention and have been widely used as sensing materials at room
J Mater Sci: Mater Electron
temperature. However, sensors with pure conducting polymers suffer from major disadvantages such as poor stability and selectivity as well as long response time [6, 7]. Hybrid nanocomposites of metal oxide semiconductors and conducting polymers, which have been investigated in re
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