Enhanced Sensitivity of NO2 Gas Sensor Utilizing Fe2O3-Embedded ZnO Nanostructures

This paper introduces a streamlined three-step synthesis method for crafting porous Fe2O3/ZnO nanofibers (NFs). Initially, Fe2O3 nanoparticles (NPs) were synthesized using the hydrothermal method. Subsequently, PVP NFs laden with Fe2O3 NPs and zinc salt were synthesized via an electrospinning method. Finally, porous Fe2O3/ZnO NFs were fabricated through calcination, resulting in an average diameter of approximately 100 nm. Gas-sensing experiments illuminate that the porous Fe2O3/ZnO NFs exhibit outstanding sensitivity, selectivity, and robust long-term stability. Although the response magnitude decreased under high relative humidity (RH) due to competitive adsorption, the sensor maintained distinct detectable responses towards NO2 vapor at an optimum temperature of 225 °C. Particularly noteworthy is the substantial enhancement in NO2 sensing properties observed in the Fe2O3/ZnO composite compared to pure ZnO NFs. This enhancement can be ascribed to the distinctive microstructure and heterojunction formed between Fe2O3 and ZnO.