Highly controllable and green reduction of graphene oxide to flexible graphene film with high strength

•Graphene was synthesized by an effective and environmentally friendly approach.•We introduced a facile X-ray diffraction analysis method to investigate the reduction process from graphene oxide to graphene.•Flexible graphene films were prepared by self-assembly of the graphene sheets.•The strength of the graphene films depends on the reduction degree of graphene.

Graphene film with high strength was fabricated by the assembly of graphene sheets derived from graphene oxide (GO) in an effective and environmentally friendly approach. Highly controllable reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant, in which the reduction process was monitored by XRD analysis and UV–vis absorption spectra. Self-assembly of the as-made CCG sheets results in a flexible CCG film. This method may open an avenue to the easy and scalable preparation of graphene film with high strength which has promising potentials in many fields where strong, flexible and electrically conductive films are highly demanded.

Graphical abstractHighly controllable and green reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant. Self-assembly of the as-made CCG sheets results in a flexible CCG film, of which the tensile strength strongly depends on the deoxygenation degree of graphene sheets.Figure optionsDownload full-size imageDownload as PowerPoint slide