▎ 摘　　要

In this work, the NH3 gas sensors based on chemically reduced graphene oxide (CRG) have been fabricated and studied. Aniline was used to reduce graphene oxide (GO) in order to obtain CRGs attached with different states of polyaniline (PANI), i.e., acid-doped PANI attached CRG, de-doped PANI attached CRG and free CRG. These various products were characterized by scanning electron microscopy, transmittance electron microscopy, infrared spectroscopy and UV-Vis spectroscopy. Furthermore, gas sensing properties of gas sensors based on these CRGs were studied. And the results suggested that free CRG exhibited excellent response to NH3 and showed high sensitivity to NH3 with the concentrations at parts-per-million (ppm) level. The sensors based on free CRG exhibited a response of 37.1% when exposure to 50 ppm of NH3. And they showed excellent recovery in comparison with the acid-doped CRG, as well. Above all, free CRG can be considered as an excellent sensing material for the detection of NH3. In addition, the sensing device can be easily fabricated by drop drying method, which holds great potential in various gas sensing fields, due to its miniature, low cost and portable characteristics. (C) 2013 Elsevier B.V. All rights reserved.