Highly Responsive and Room-Temperature Operable Ethanol Gas Sensor Based on Thermally Reduced Graphene Oxide

Abstract

Herein, we report the successful detection of ethanol among the variety of Volatile Organic Compounds (VOCs) namely isopropanol, toluene and acetone at room temperature (RT) via a thermally reduced graphene oxide (T-RGO) based sensor. T-RGO material was prepared by the thermal reduction of graphene oxide (GO) at 250 °C for 20 min. The properties of as-synthesized T-RGO were elucidated by X-ray diffraction, Raman spectroscopy, FT-IR spectroscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy and Brunauer–Emmett–Teller (BET) techniques. The BET analysis of T-RGO revealed the mesoporous structure with specific surface area of 86.21 m2 g−1. The proposed T-RGO sensor was exposed to various ethanol concentrations ranging from 5 to 100 ppm and the sensor exhibited maximum response (15%) towards 100 ppm of ethanol at RT. The high sensitivity, fast response (3 s)/recovery time (6 s) and excellent repeatability of ethanol, suggest its good selectivity over other tested VOCs. The optimum operating temperature of the sensor was found to be RT (28 °C). Upon exposure to different relative humidity (RH) levels, the ethanol sensing response was found to vary only by 1.5% from 33% to 83% RH, indicating low dependence of humidity on the sensor performance. In addition, the sensor displayed efficient long-term stability towards ethanol at RT.