Au-modified α-Fe2O3 nanoparticles for ultrasensitive isopropanol detection

Abstract

As a typical VOC gas, the harm of isopropanol to human health and the environment cannot be ignored. The detection of isopropanol is of great significance to human safety and environmental protection. Herein, Au/α-Fe₂O₃ sensors with different Au contents were prepared for isopropanol detection using a simple microwave-assisted method. The morphology, structure, and composition of the samples were characterized using SEM, TEM, XRD, and XPS. The gas-sensitive properties of pure α-Fe₂O₃ and Au/α-Fe₂O₃ composites were systematically investigated under different temperatures. It was found that the Au/α-Fe₂O₃ composite (AF) sensors exhibited excellent selectivity and a high response to isopropanol at an optimal operating temperature of 220 °C. The gas-sensing performances of the Au-modified α-Fe₂O₃ nanoparticles were significantly improved compared to that of pristine α-Fe₂O₃. Especially, the sample with the Au-modified concentration of 7 mol% exhibited the highest response of 51.47 to 100 ppm isopropanol, which was 4.5 times higher than that of pure α-Fe₂O₃. Moreover, the AF gas sensor displayed great selectivity, reusability, and long-term stability. The enhancement of the gas-sensing performances of the AF composite gas sensors can be attributed to the effects of electronic sensitization and chemical sensitization induced by the introduction of Au nanoparticles, providing a viable solution for detecting isopropanol.