We report a one-step fabrication of macroscopic multifunctional graphene-based hydrogels with robust interconnected networks under the synergistic effects of the reduction of graphene oxide sheets by ferrous ions and in situ simultaneous deposition of nanoparticles on graphene sheets. The functional components, such as α-FeOOH nanorods and magnetic Fe(3)O(4) nanoparticles, can be easily incorporated with graphene sheets to assemble macroscopic graphene monoliths just by control of pH value under mild conditions. Such functional graphene-based hydrogels exhibit excellent capability for removal of pollutants and, thus, could be used as promising adsorbents for water purification. The method presented here is proved to be versatile to induce macroscopic assembly of reduced graphene sheets with other functional metal oxides and thus to access a variety of graphene-based multifunctional nanocomposites in the form of macroscopic hydrogels or aerogels.

Free-standing graphene paper with a grey metallic luster has been fabricated for the first time, by a convenient one-step method on a large scale. Herein, the assembly of graphene oxide dispersion into ordered paper occurs simultaneously with the chemical reduction of graphene oxide to graphene. The graphene paper presents the advantages of good flexibility, low weight (0.2 g cm À3 ) and high electrical conductivity (15 U sq À1 ). Moreover, the size and shape of the graphene paper are freely exchanged for those of the Teflon substrate used. The flexible graphene-PANI paper subsequently exhibits excellent supercapacitor performance with an enhanced specific capacitance (763 F g À1 ) and good cycling stability by electropolymerization of PANI nanorods on the above graphene paper. The method presented here shows great promise for the development of low-cost electrode materials in potential energy storage devices. Broader contextAttracted by the increasing demand for portable energy storage devices, great efforts have been paid to the exploration of energetic carbon-based materials for application in supercapacitors with the benets of low cost, facile scale-up preparation, easy processability, high specic capacitance and high charge-discharge cycling stability. Graphene and polyaniline (PANI) are good candidates for electrical double-layer capacitors (EDLCs) and pseudocapacitors, respectively. In this work, we develop for the rst time an extremely simple one-step reduction-assembly method for the preparation of exible graphene paper with ordered microstructure on a large scale, possessing the advantages of low weight (0.2 g cm À3 ) and high electrical conductivity (15 U sq À1 ). The subsequent exible graphene-PANI paper, formed by electropolymerization of PANI nanorod arrays on the above graphene paper, exhibits an enhanced specic capacitance and high cycling stability as a supercapacitor. The perfect integration of two types of capacitor materials into exible macroscopic-scale graphene-PANI composite paper with arbitrary dimensions satises the requirements of high-quality electrode materials and takes us much closer to portable energy storage devices with practical applications.

Graphene is now the most attractive carbon-based material. Integration of 2D graphene sheets into macroscopic architectures such as fibers illuminates the direction to translate the excellent properties of individual graphene into advanced hierarchical ensembles for promising applications in new graphene-based nanodevices. However, the lack of effective, low-cost and convenient assembly strategy has blocked its further development. Herein, we demonstrate that neat and macroscopic graphene fibers with high mechanical strength and electrical conductivity can be fluidly spun from the common graphene oxide (GO) suspensions in large scale followed with chemical reduction. The curliness-fold formation mechanism of GO fiber has been proposed. This wet-spinning technique presented here facilitates the multifunctionalization of macroscopic graphene-based fibers with various organic or inorganic components by an easy-handle in situ or post-synthesis approach, which builds the solid foundation to access a new family of advanced composite materials for the next practical applications.