Lattice expansion of graphite oxide by pressure induced insertion of liquid ammonia

A pressure induced lattice expansion of Graphite Oxide (GO) in presence of NH3 was observed by X-ray diffraction during room temperature compression and decompression up to 7 GPa in a diamond anvil cell (DAC). A remarkable increase (∼11%) of the interlayer d-spacing of GO was observed between 0.2 and 1.1 GPa in the liquid phase of NH3, indicating the occurrence of molecular insertion between the GO layers. The expansion is reversible with the release of pressure, thus leading to a pressure induced breathing of the GO lattice. The presence of high density NH3 between the GO layers opens new perspectives for N-doping and chemical functionalization of GO and for designing new advanced carbon based nanostructured materials.