α-Fe2O3 loaded less-defective graphene sheets as chemiresistive gas sensor for selective sensing of NH3

α-Fe2O3 functionalized, less-defective graphene sheets have been synthesized by a cost effective green solvent-assisted ultrasonication induced graphite exfoliation followed by hydrothermal method and its chemiresistive ammonia gas sensing properties have been investigated. The less-defective nature of graphene and the strong interaction of aromatic graphene network with α-Fe2O3 have been revealed from Raman spectroscopic and XPS and Raman spectroscopic analyses. The α-Fe2O3/graphene nanocomposite exhibited outstanding chemiresistive sensing properties towards NH3 gas, which is a toxic industrial pollutant. High sensor response, selectivity and repeatability are offered by the α-Fe2O3/graphene nanohybrid towards NH3 gas at 250 °C. The sensor response was linear in the range of 10–50 ppm with a regression coefficient of 0.95. A plausible sensing mechanism is suggested, indicating the role of both α-Fe2O3 and graphene leading to a synergistic response towards NH3.