Graphite oxide is an amorphous insulator. Although several models have been suggested, its structure remains controversial. To elucidate this issue, 5 samples were prepared by the Brodie process and the Staudenmaier process. The electronic structure of graphite oxide was examined with x-ray absorption near edge structure and the ratio of sp 2 to sp 3 bonded carbon atoms was investigated with x-ray photoemission spectroscopy as a function of sample preparation times. It was found that this ratio approaches 0.3 exponentially with a characteristic time of 1.5 weeks. We believe this long characteristic time is the reason the structure has remained unclear.

We investigated the reaction of graphite oxide with water molecule in the air with X-ray diffraction, solid-state nuclear magnetic resonance, and Fourier transform infrared spectroscopy. X-ray diffraction data show that the layer distance of graphite oxide increases when it becomes hydrated in the air. Solid-state nuclear magnetic resonance and Fourier transform infrared spectra reveal that hydrated graphite oxide in the air has phenol groups on its layer edges. The overall results indicate that graphite oxide reacts with water molecules in the air and phenol groups are formed in graphite oxide.