Highly sensitive ethylene sensors using Pd nanoparticles and rGO modified flower-like hierarchical porous α-Fe2O3

To develop a feasible approach to detect ethylene in low concentration is of great significance to reduce losses of farm products during storage and logistics. However, it is really difficult to detect it due to the lack of polar chemical functionality of ethylene and its small size. While appropriate Pd nanoparticles (NPs) and reduced graphene oxide (rGO) modified flower-like hierarchical porous α-Fe2O3 was designed and successfully synthesized in this article, which can detect ethylene with high sensitivity and low temperature. Experiment results reveal that Pd/rGO/α-Fe2O3 can detect ehylene in the concentration as low as 10 ppb, which is the best one among all the ethylene gas sensors and has made a major breakthrough in the detection limit of ethylene. Besides, other sensing performance, including operation temperature (250 °C), the response-recovery time (18 s and 50 s), and examination range (from 10 ppb to 1000 ppm) all have been significantly improved. The high specific surface area of flower-like hierarchical porous structure, the catalysis of Pd nanoparticles, and chemically active defect sites of rGO all contribute to the high sensing performances of Pd/rGO/α-Fe2O3 in detecting ethylene. These do provide a practical method for detecting low concentrations of ethylene and make it more competitive to detect ethylene with low cost and convenient gas sensors.