Enhancement of p-type gas-sensing performances of NiO nanoparticles prepared by precipitation with RuO2 impregnation

In this work, 0-1.00 wt% Ru-loaded nickel oxide nanoparticles were synthesized by the chemical precipitation/impregnation methods and systematically characterized for gas-sensing applications. Characterizations by electron microscopy, X-ray diffractometry, X-ray photoemission spectroscopy showed that primary particles were face-centered-cubic structure of NiO and RuO2 nanoparticles were dispersed within larger NiO NPs. Nitrogen adsorption studies also revealed that specific surface area of RuO2/NiO nanoparticles increased with increasing Ru content. Gas-sensing measurement showed that increasing Ru loading content considerably improved C2H5OH response and selectivity against H2S, NO2, SO2, H-2, and NH3 at an operating temperature of 350 degrees C. In particular, the NiO sensor with the highest Ru content of 1.00 wt% showed a high p-type sensor response of 35.9-2000 ppm C2H5OH at 350 degrees C, which was about three times as high as that of unloaded one. Therefore, RuO2 loading by impregnation is an effective mean to improve the gas-sensing performances of p-type NiO-based gas sensors. (C) 2016 Elsevier B.V. All rights reserved.