Synthesis of Reduced Graphite Oxide by a Novel Green Process Based on UV Light Irradiation

We have developed a novel and straightforward approach for the green synthesis of reduced graphite oxide (rGO). First, graphite oxide (GO) was prepared by the Hummers' oxidation method, starting from high-surface-area graphite. Then, rGO was generated from GO in aqueous suspension through a UV-irradiation treatment. The influence of different process parameters (including type of UV source, irradiation time and atmosphere) on the GO reduction efficiency was explored and evaluated on the basis of the data acquired by several experimental techniques, such as infrared spectroscopy in attenuated total reflectance mode, X-ray diffraction, UV-vis absorption spectrophotometry, X-ray photoelectron spectroscopy and thermogravimetry. The acquired results allowed identifying appropriate sets of reaction conditions under which GO reduction yield could be maximized. In particular, the highest reduction degree was obtained by exposing GO to UV light in a UV oven for 48 h under inert atmosphere. The reduction strategy developed by us represents an innovative low-cost and easy route to graphene-based nanomaterials, which does not require any stabilizer, photocatalyst or reducing agent. For this reason, our method represents an attractive environmentally friendly alternative approach for the preparation of stable rGO dispersions in large-scale amounts, to be utilizable in disparate engineering applications.