▎ 摘　　要

Chemical reduction of graphene oxide can be applied for the bulk preparation of reduced graphene oxide for potential application in various graphene-based materials. However, this approach usually involves toxic reducing agents that are harmful to human health and the environment. Here, we report a facile one-pot reduction of graphene oxide using lemon extract as a green and natural reducing agent, and the reduction experiments were conducted under mild conditions. The structure, morphology and, de-oxidation efficiency of the obtained reduced graphene oxide samples were characterized by X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Field emission transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Thermogravimetric analyzer. The results demonstrated the formation of few-layered reduced graphene oxide nanosheets and the efficient removal of oxygen-containing functional groups decorated on graphene oxide. After reduction by lemon extract, the carbon to oxygen ratio of samples dramatically increased from 1.36 of graphene oxide to 4.66 of reduced graphene oxide, further proving that the lemon extract can effectively facilitate the de-oxygenation of graphene oxide, resulting in water molecules and reduced graphene oxide with sp(2)-bonded carbon atoms. This method avoided the use of any nocuous chemicals during the reduction experiments, thus facilitating the mass production of graphene and graphene-based materials.