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

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.