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

Abstract We investigated the gas-sensing properties of gold nanoparticles decorated VO 2 nanowires sensor to NO 2 at room temperature. The vanadium dioxide nanowires were synthesized by a chemical vapor deposition method and Au nanoparticles were decorated on VO 2 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 VO 2 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 VO 2 nanowires sensor exhibits the highest sensitivity to NO 2 at 0.5–5 ppm and the optimal operating temperature is room temperature (25 ℃). The enhancement in response was attributed to the “spillover effect” and the change of depletion layer caused by Au nanoparticles. The 10s-Au decorated VO 2 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 VO 2 nanowires. This study may provide guidelines for the development of new metal decorated gas sensors.