A novel nanoporous carbon-silica composite with medium hydrophilicity is synthesized by a series of methods consisting of preexpansion of the interlayer of graphite oxide (GO) by surfactant intercalation, the intercalation of tetraethoxylsilane (TEOS) and its hydrolysis in the interlayer, followed by post carbonization to form a robust bridged/pillared network. High-resolution N 2 adsorption results show that carbonization at 823 K gives a composite having the highest specific surface area of more than 1000 m 2 /g with both microporosity and mesoporosity. Varieties of analytical results using DRIFT, NMR, XPS, and RAMAN spectra indicate that this composite contains small graphene sheets in its structure and its silicon components are silica particles with +4 valence. Morphology observation, thermal desorption, and other properties suggest the important roles of dispersion of GO in aqueous solution, preexpansion of GO interlayer, interlayer hydrolysis of TEOS molecules, and the carbonization condition in the formation mechanism of this nanoporous composite.

The structural and surface properties of a hydrous hollandite-type manganese oxide (H-Hol) were examined by adsorption using different gases with molecular diameters below 0.4 nm. N 2 , O 2 , Ar, CO, and CO 2 with diameters above 0.33 nm are excluded from the tunnel structure of H-Hol, whereas H 2 O and NH 3 with diameters below 0.265 nm can be inserted into the structure. Disagreements were observed for the first and second run adsorption isotherms of H 2 O and NH 3 , indicating that there is a strong interaction contributing to H 2 O and NH 3 adsorption. Insertion of NH 3 into the tunnels of H-Hol is a very slow process; the rate-determining step is that of insertion into the inner H + sites. H + sites on H-Hol play an important role in both NH 3 and H 2 O adsorption. Adsorption and FT-IR results demonstrate that stepwise dehydration decreases the H + sites available for NH 3 adsorption, some but not all of which are recoverable by rehydration.

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