A Highly Selective and Sensitive H2S Gas Sensor Based on Novel Nanostructure Core-Shell FeCr2O4@ZnO@MgO

Gas detection is significant for controlling industrial and vehicle emission, house equipment security and environmental monitoring. Various devices are developed and designed for detection of CO2, CO, SO2, O-2, O-3, H-2, NH3, and several other organic gases. The fabrication of FeCr2O4, FeCr2O4@ZnO, and FeCr2O4@ZnO@MgO core-shell nanostructure by sol-gel method and their gas sensing performance using thick films were reported here for the first time. The characterization was completed by means of X-ray diffraction (XRD), Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and Transmission electron microscopy (TEM) used for confirmation of crystal structure and their morphology. The synthesized oxides were formulated to identify various air pollutants including CO, CO2, Cl-2, NH3, H-2, and H2S. The influences of thermal annealing (300-500 degrees C) on the crystallization and H2S gas sensing performance were investigated. Among the three oxides studied, 355.08 is the sensitivity for FeCr2O4, 461.12 for FeCr2O4@ZnO and highest sensitivity was observed for FeCr2O4@ZnO@MgO core-shell sensor for H2S gas (500 ppm) is 597.17. The sensitivity of the measurements to relative humidity as an interfering parameter was also investigated.

Automated summary

Gas detection is important for various applications, and in this study, FeCr2O4, FeCr2O4@ZnO, and FeCr2O4@ZnO@MgO core-shell nanostructures were synthesized and tested for gas sensing performance. Characterization through XRD, FT-IR, SEM, EDX, and TEM confirmed the crystal structure and morphology of the synthesized oxides, which showed promising sensitivity to different gases. Thermal annealing and humidity effects on the sensing performance were also investigated.