Synthesis of highly sensitive ammonia gas sensor of polyaniline/graphene nanoribbon/indium oxide composite at room temperature

Abstract

Indium trioxide (In2O3) nanoparticles prepared using a solvothermal reaction were coated on the surface of graphene nanoribbon (GNR) to serve as a core for the manufacture of polyaniline (PANI)/In2O3/GNR ternary nanocomposites produced using in situ chemical oxidative polymerization. The gas-sensing properties of nanocomposites were evaluated by a homemade dynamic test system at room temperature, which was equipped with a real-time resistance acquisition platform. The response value of the PANI/In2O3/GNR sensor with the loading of 3 wt% In2O3 nanoparticles and an exposure of 4 ppm NH3 was 27.1, which was about 3 or more times higher than that of PANI sensor. This sensor was shown to be very sensitive to the detection of NH3 in the concentration range of 0.65–1.69 ppm at room temperature, which is critical in the detection of hepatic or kidney disease in the human breath. The PANI/In2O3/GNR sensor also revealed higher selectivity and repeatability when exposed to 0.65 ppm NH3 at room temperature. Because of the excellent selectivity and repeatability in the detection of 0.65 ppm NH3 at room temperature obtained in this report, it is believed that the PANI/In2O3/GNR nanocomposites sensor will be a promising gas-sensing material for the detection of hepatic or kidney disease in human breath.