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, 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 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.