Room temperature selective detection of NO2 using Au-decorated In2O3 nanoparticles embedded in porous ZnO nanofibers

A series of porous Au nanoparticles (NPs) decorated with In2O3 nanoparticles (NPs) was embedded in ZnO nanofibers (NFs) using a facile electrospinning method, followed by calcination treatment at 400 °C. The crystal phase structure, morphology, elemental composition, and specific surface area were characterized using FESEM, XRD, FETEM, XPS, and BET analysis. The gas-sensing properties of the resulting Au-In2O3-ZnO NFs-based gas sensors were systematically assessed. The results showed that a small amount of In2O3 dopant improved the gas-sensing response properties. In particular, the sensor fabricated with a mixture containing 0.03 g In(NO3)3 (S2) exhibited excellent stability, selectivity, and a response of 95.15 towards 5 ppm of NO2 gas at room temperature (RT, 25 ℃) under ultraviolet (UV) irradiation. The S2 sensor also showed a high response of 90–5 ppm of NO2 at 80% relative humidity (RH). The high response sensing performance at low operating temperature (RT) of the fabricated Au-In2O3-ZnO sensors may be due to a synergistic effect between ZnO and In2O3, as well as the excellent catalytic effect of Au.