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Two-dimensional graphene nanosheets and graphene-based materials have garnered significant attention in recent years due to their excellent materials properties.[1] Many graphenebased materials can be conveniently synthesized from graphite oxide (GO), which can be prepared in bulk quantities from graphite under strong oxidizing conditions.[2–5] GO is a layered material featuring a variety of oxygen-containing functionalities with epoxide and hydroxyl groups on the basal plane and carbonyl and carboxyl groups along the edges,[6, 7] which provide a platform for rich chemistry to occur both within the intersheet gallery and along sheet edges.[8–10] In addition, GO can be easily exfoliated into individual graphene oxide sheets, which can be reassembled into thin films [11] or paper-like materials. For the latter case, flow-directed filtration of an aqueous graphene oxide dispersion produces very large sheets of a free-standing, foil-like material known as graphene oxide paper.[12] This paper retains all the functional groups found in GO, preserving all of its native chemistry.

While graphene oxide paper can be chemically modified in a facile fashion and has good mechanical properties, it was found to be electrically conductive only after thermal annealing, which presumably converts it into graphene paper.[13] Unfortunately, this thermal treatment also degrades its structural integrity. Graphene paper, fabricated via flow-directed filtration of an electrostatically stabilized aqueous graphene dispersion [13] that was pre-prepared via hydrazine reduction of graphene oxide sheets, has excellent electrical conductivity and similar mechanical properties …