2 December 2020

Room temperature detection of NO2 gas under UV irradiation based on Au nanoparticle-decorated porous ZnO nanowires

ZnO nanowires were prepared by oxidized ZnS nanowires. The sensing performance of

these ZnO nanowires for NO2 gas was enhanced by decorating Au nanoparticles on their

surface. The scanning electron microscopy results revealed that diameter and length of the

ZnO nanowires showed 150e200 nm and up to a few hundreds of mm, respectively. The

diameters of Au nanoparticles which were decorated on the ZnO nanowires were 5e20 nm

and they were distributed evenly on the surface of the nanowires. The transmission

electron microscopy results revealed that the ZnO nanowires obtained after 2 h of the

oxidation treatment process were composed of lots of nanograins with a diameter of 50

e100 nm, which rendered the surface of the nanowires rough and full of void spaces. The

hierarchical structure of the nanowires increased their surface-to-volume ratio and

contributed to the adsorption of gas on their surface, improving their sensing performance.

In this study, the NO2 gas sensing mechanism of the Au nanoparticle-decorated ZnO

nanowires sensors were investigated under UV illumination at room temperature.