Enhanced NOx Gas Sensing Performance Based on Indium-Doped Co(OH)2 Nanowire-Graphene Nanohybrids

In this paper, the In(OH)(3)/Co(OH)(2)/rGO (ICG) nanohybrids have been synthesized via a simple reflux method. It was found that the nanostructures were actually composed of thin nanosheets or nanowires. The addition of indium in Co(OH)(2) on rGO results in increase in the specific area of nanohybrids (105.7 m(2) g(-1)). That enhanced the gas sensing responses to NOx compared with Co(OH)(2)/rGO significantly. The ICG nanohybrids with the mass ratio of 5:1 (ICG-5) exhibited excellent gas-sensing properties with low detection limit of 0.97 ppm and high sensitivity of 75.32% to 97 ppm NOx at room temperature (RT). The gas sensor also showed excellent selectivity to NOx when other common gases such as NH3, CO, C2H2 and H-2 were present. The sensing mechanism could be attributed to the charge carrier concentration of Co(OH)(2) greatly increased by indium doping, which at last encourages the electron transfer during the interaction with gases.