Fabrication of C₂H₂Gas Sensors Based on Ag/ZnO-rGO Hybrid Nanostructures and Their Characteristics

Abstract

In this work, pure hierarchical ZnO structure was prepared using a simple hydrothermal method, and Ag nanoparticles doped hierarchical ZnO structure was synthesized uniformly through photochemical route. The reduced graphene oxide (rGO) has been synthesized by typical Hummer's method and reduced by hydrazine. Prepared Ag/ZnO nanostructures are uniformly dispersed on the surface of rGO sheets using ultrasonication process. The synthesized samples were characterized by SEM, TEM, EDS, XRD and PL spectra. The average size of prepared ZnO microspheres was around 2~3 µm and showed highly uniform. The average size of dopedAg nanoparticles was 50 nm and decorated into ZnO/rGO network. The C 2 H 2 gas sensing properties of as-prepared products were investigated using resistivity-type gas sensor. Ag/ZnO-rGO based sensors exhibited good performances for C 2 H 2 gas in comparison with the Ag/ZnO. The C 2 H 2 sensor based on Ag/ZnO-rGO had linear response property from 3~1000 ppm of C 2 H 2 concentration at working temperature of 200 o C. The response values with 100 ppm C 2 H 2 at 200 o C were 22% and 78% for Ag/ZnO and Ag/ZnO-rGO, respectively. In additions, the sensor still shows high sensitivity and quick response/recovery to C 2 H 2 under high relative humidity conditions. Moreover, the device shows excellent selectivity towards to C 2 H 2 gas at optimal working temperature of 200 o C.Keywords: Ag-doped ZnO microspheres, Graphene-hybrid nanostructures, Hydrothermal method, Photochemical reduction, C 2 H 2 gas sensor 1. 서 론 Received: Nov. 17, 2014, Revised: Jan. 12, 2015, Accepted: Jan. 14, 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/ licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.