Facile one-step hydrothermal synthesis and room-temperature NO2 sensing application of α-Fe2O3 sensor

An alpha-iron oxide (α-Fe2O3) film-sensor prepared by a simple one-step hydrothermal synthesis technique demonstrates a high selectivity and sensitivity toward NO2 at room-temperature (27 °C). The XRD pattern of the as-synthesized sensor endows polycrystalline nature and hematite crystal structure. The gas sensing properties of α-Fe2O3 sensor are investigated against various target gases viz. hydrogen (H2), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon dioxide (CO2), liquefied petroleum gas (LPG), and carbon monoxide (CO). Due to a high specific surface area, special structure, and high electron contributing power over other tested gases, α-Fe2O3 sensor exhibits a high response, with good response/recovery time for NO2 gas. The α-Fe2O3 sensor shows 86% response for 100 ppm concentration of NO2 gas with excellent response/recovery time (31/32 s) and reported. The α-Fe2O3 sensor performance is measured for various concentration levels of NO2 gas. The theoretically proposed gas sensing mechanism also suggests a better response of the α-Fe2O3 sensor to NO2 gas over other gases. The room-temperature sensing operation, high selectivity, moderate repeatability and short response/recovery time with cost-effectiveness followed scalable synthesis of α-Fe2O3 sensor would decidedly useful for social and commercial benefits.