A low temperature and highly sensitive ethanol sensor based on Au modified In2O3 nanofibers by coaxial electrospinning

Gas sensing is a powerful tool for detecting the leakage of some hazardous gases and monitoring human health. However, most of the sensors based on metal oxide semiconductors can only function at elevated operating temperatures, which leads to high power consumption and poor durability. Here, Au nanoparticle decorated In2O3 nanofibers (IO-Au NFs) have been successfully synthesized by one-step coaxial electrospinning for efficient sensing of ethanol gas at low temperature. The temperature and gas concentration effects on the sensing properties of the IO-Au NFs confirm that the Au decoration can remarkably improve the response, reduce the detection limit down to 1 ppm, and lower the sensors' optimal operating temperature down to 175 degrees C. The IO-Au-0.42 sensor with the optimized Au concentration presents a superior response of 116.13 to 100 ppm ethanol at 175 degrees C, which is six times larger than that of the pristine In2O3 sensor. Moreover, the IO-Au-0.42 sensor exhibits a much shorter response/recovery time of 2 s/152 s to 100 ppm ethanol gas at 175 degrees C than the pristine In2O3. Surprisingly, even at room temperature, the IO-Au-0.42 sensor still presents a high response of 11.12 to 100 ppm ethanol, which is 5.4 times larger than that of the pristine In2O3 sensor, and shows a short response/recovery time of 47 s/351 s. This enhanced sensing performance at low temperature can be mainly ascribed to the synergistic action of the catalytic effect, spillover effect, electronic sensitization effect, and deficient oxygen concentration.