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 wasobserved by X-ray diffraction during room temperature compression and decompressionup to 7 GPa in a diamond anvil cell (DAC). A remarkable increase (~11%) of the interlayerd-spacing of GO was observed between 0.2 and 1.1 GPa in the liquid phase of NH3, indicat-ing the occurrence of molecular insertion between the GO layers. The expansion is rever-sible with the release of pressure, thus leading to a pressure induced breathing of the GOlattice. The presence of high density NH3 between the GO layers opens new perspectivesfor N-doping and chemical functionalization of GO and for designing new advanced carbonbased nanostructured materials.