Specific intermolecular structures of gases confined in carbon nanospace Original Research Article

The role of the nanospace of activated carbon in molecular and surface sciences is described with relevance to the role of the graphite surface in surface science. The reason why the carbon nanospace is effective for the control of gases is explained using molecular potential theory. The following examples of organized structure formation of gases confined in carbon nanospaces, which were determined by in situ X-ray diffraction, magnetic susceptibility, and molecular simulation techniques, are given. Helium forms a high-density structure in carbon nanospace at 4.2 K; the adsorbed density is nearly twice that of the bulk liquid density. Even at 300 K, sufficient amounts of supercritical Xe can be adsorbed in carbon nanospace through cluster formation. Supercritical NO can also be adsorbed at 303 K in carbon nanospace in the form of the dimer and the highly concentrated NO decomposes rapidly into N2, even at 303 K. The solid-like ordered structures of confined water and C2H5OH are shown. The solid-like structure of confined water is confirmed by the temperature dependence of the electron radial distribution function.