Selective determination of ammonia, ethanol and acetone by reduced graphene oxide based gas sensors at room temperature

This work reports a new technique for the selective determination of three organic vapors- ammonia, ethanol and acetone by employing two resistive sensors. These two resistive sensors are based on reduced graphene oxide (RGO) and RGO- rosebengal (RB) composites. The chemically synthesized RGO and RGO-RB based sensors were tested for four different concentrations of ammonia (400-2800 ppm) and two different concentrations (1000, 2000 ppm) of ethanol and acetone each, at room temperature. The RGO sensor was found to exhibit response of 10.3% to 25.3% to 400-2800 ppm of ammonia, 1.01% to 1.15% to 1000 and 2000 ppm of acetone respectively, and 1.05% to 1.56% to 1000 and 2000 ppm of ethanol respectively. The RGO-RB composite-based sensor exhibited an enhanced response ranging from similar to 17% to 36.6% for 400-2800 ppm of ammonia, 1.6% to 3.2% for 1000 and 2000 ppm of acetone and 1.1% to 1.7% for 1000 and 2000 ppm of ethanol at room temperature. An algorithm, based on the soft margin classifier was developed to accurately determine the concentrations of all the three organic vapors. The initial 100 s of the response values of both the sensors for all the targeted vapors were considered for this purpose. This resulted into classification of all the concentrations of the three organic vapors much before the full-scale response of the sensors. It is believed that this work will aid in development of portable devices comprising of array of sensors having the capability of determining the vapors and their concentrations accurately.