Synthesis and solid-state NMR structural characterization of 13C-labeled graphite oxide

The detailed chemical structure of graphite oxide ( GO), a layered material prepared from graphite almost 150 years ago and a precursor to chemically modified graphenes, has not been previously resolved because of the pseudo- random chemical functionalization of each layer, as well as variations in exact composition. Carbon-13 (C-13) solid- state nuclear magnetic resonance ( SSNMR) spectra of GO for natural abundance C-13 have poor signal- to- noise ratios. Approximately 100% C-13- labeled graphite was made and converted to C-13- labeled GO, and C-13 SSNMR was used to reveal details of the chemical bonding network, including the chemical groups and their connections. Carbon-13-labeled graphite can be used to prepare chemically modified graphenes for C-13 SSNMR analysis with enhanced sensitivity and for fundamental studies of C-13-labeled graphite and graphene.