Synthesis Of Superior Dispersible Reduced Graphene Oxide

Graphene is a novel two-dimensional inorganic material with a mono-layer carbon atom. Dueto its outstanding mechanical, electrical, thermal and optical properties, graphene shows promisingapplications in electronic devices, biological and envioronmental material, energy storage andadvanced composites. To date, many approaches to the preparation of graphene has been reported,including micromechanical exfoliation, chemical vapour deposition, epitaxial growth, un-zippingcarbon nanotubes and the chemical reduction of graphene oxide (GO). Among them, the chemicalreduction of GO exhibited easy operation, high yield, low cost and the potential of large-scalepreparation, showing excellent industrial application prospect. However, there are two problems tobe addressed for practical applications. Firstly, many widely-employed reductants are toxic,hindering the applications of products in the field of biology and environment. On the other hand,the resulting reduced-graphene oxide (rGO) displayed poor dispersibility. Aiming at these twoissues, the following researches were performed in this dissertation.Superior dispersions of rGO were prepared by using natural gallic acid as a reductant andstabilizer through chemical reduction, the dispersibility of which was up to1.2mg/mL in water and4mg/mL in DMSO. Moreover, superior dispersions of rGO were also prepared with natural rutin asa reductant and stabilizer. Their dispersibility was up to1.5mg/mLin water and4mg/mLin DMSO.The effective reduction of GO suspensions by natural gallic acid or rutin was verified by UV-vis, IR,Raman, XPS, XRD, SAED and TGA. Besides, the thickness and morphology of the resultant rGOwas investigated byAFM and TEM.The molecules of gallic acid or rutin were absorbed on the rGO sheets as stabilizer because of theπ–π interactions between the rGO sheet and their aromatic structural moieties, thus the rGO sheetsdisplayed strong electronegativity, which hindered the stacking of rGO sheets. As a result, theresulting rGO possessed high dispersibility, exhibiting excellent application prospect in biologicaland environmental materials. In addition, the graphene-based gels were prepared by the reduction ofGO with rutin. They presented excellent absorption performance of oil and solvent, which could be applied in the recovery of oil and solvent.