Room temperature NO2 sensing properties of Au-decorated vanadium oxide nanowires sensor

摘要

We investigated the gas-sensing properties of gold nanoparticles decorated VO2 nanowires sensor to NO2 at room temperature. The vanadium dioxide nanowires were synthesized by a chemical vapor deposition method and Au nanoparticles were decorated on VO2 nanowires via an ion sputtering method at different sputtering time (10 s, 20 s, 30 s). Field emission scanning electron microscope and X-ray diffraction were used to characterize the morphology and crystal structure of the compositions. The results show that VO2 nanowires are monoclinic crystal structures and the size and amount of Au nanoparticles are affected by sputtering time. The gas-sensing characteristics were tested via a home-made static gas-sensing system. It is found that the 10s-Au decorated VO2 nanowires sensor exhibits the highest sensitivity to NO2 at 0.5-5 ppm and the optimal operating temperature is room temperature (25 degrees C). The enhancement in response was attributed to the "spillover effect" and the change of depletion layer caused by Au nanoparticles. The 10s-Au decorated VO2 nanowires has the best response due to the small size and the high amount of Au nanoparticles accelerate the dissociation and adsorption of oxygen on the surface of VO2 nanowires. This study may provide guidelines for the development of new metal decorated gas sensors.