Facile Hydrothermal Synthesis of Two-Dimensional Porous ZnO Nanosheets for Highly Sensitive Ethanol Sensor

Nguyen Van Hieu,Nguyen Hong Hanh,Nguyen Duc Hoa,Dang Ngoc Son,Nguyen Van Duy,Chu Manh Hung,Lai Van Duy,Pham Tien Hung

doi:10.1155/2019/4867909

Nguyen Van Hieu, Nguyen Hong Hanh + Show 6 more

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https://doi.org/10.1155/2019/4867909

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Abstract

Two-dimensional porous ZnO nanosheets were synthesized by a facile hydrothermal method for ethanol gas-sensing application. The morphology, composition, and structure of the synthesized materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and high-resolution transmission electron microcopy. Results showed that the synthesized ZnO materials were porous nanosheets with a smooth surface and a thickness of 100 nm and a large pore size of approximately 80 nm. The as-prepared nanosheets, which had high purity, high crystallinity, and good dispersion, were used to fabricate a gas sensor for ethanol gas detection at different operating temperatures. The porous ZnO nanosheet gas sensor exhibited a high response value of 21 toward 500 ppm ethanol at a working temperature of 400°C with a reversible and fast response to ethanol gas (12 s/231 s), indicating its potential application. We also discussed the plausible sensing mechanism of the porous ZnO nanosheets on the basis of the adopted ethanol sensor.

Highlights

Semiconductor metal oxide materials are drawing considerable attention for the development of sensors toward applications in numerous fields, such as air quality control, environmental monitor, and public safety from hazardous gases (e.g, NOx, SOx, COx, and H2S) [1,2,3,4,5,6]
Substantial effort has been devoted to the fabrication of metal oxide-based gas sensors for volatile organic compound (VOC) monitoring, such as benzene, toluene, acetone, methanol, and ethanol [7,8,9,10,11]
We develop a simple hydrothermal method for synthesizing porous zinc oxide (ZnO) nanosheets for effective ethanol gas sensing in industry applications

Summary

Introduction

Semiconductor metal oxide materials are drawing considerable attention for the development of sensors toward applications in numerous fields, such as air quality control, environmental monitor, and public safety from hazardous gases (e.g, NOx, SOx, COx, and H2S) [1,2,3,4,5,6]. Studies have been attempting to adjust the properties of these gas-sensitive nanomaterials and to form new multifunctional nanostructures. Such nanostructures and/or quantum dots exhibit many attractive features, such as high chemical and thermal stability, large surface area, adjustable electronic state, quantum confinement, high electron mobility, and excellent catalytic properties [11, 12]. ZnO is a potential sensing material because of its outstanding properties; it is an environmentally friendly n-type semiconductor that has a direct and wide band gap of 3.37 eV, interenergy large exciton at room temperature (~60 meV), high thermal and chemical stability, high electronic mobility, ease of synthesis, low cost, high sensitivity to target gases, and large surface-to-volume ratio [10, 17, 18].

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