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 degrees 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 gassensing 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 celcius) 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.