Phase transition in porous electrodes. III. For the case of a two component electrolyte.

The electrochemical thermodynamics of electrolytes in porous electrodes is qualitatively different from that in the bulk with planar electrodes when the pore size is comparable to the size of the electrolyte ions. In this paper, we discuss the thermodynamics of a two component electrolyte in a porous electrode by using Monte Carlo simulation. We show that electrolyte ions are selectively adsorbed in porous electrodes and the relative concentration of the two components significantly changes as a function of the applied voltage and the pore size. This selectivity is observed not only for the counterions but also for the coions.

Dissolution-aggregation behavior of water-soluble nanographites and their adsorptive characteristics for 2-naphthol in aqueous solutions.

Carbon black was severely oxidized by concentrated nitric acid at 373 K, and the oxidation product was fractionated by ultrafiltration into five groups of a few nanometer-sized water-soluble aromatic compounds, which we called water-soluble nanographites (WSNG1-5). Most WSNGs dissolve in neutral and alkaline 0.1 moldm(-3) NaCl solutions, but precipitate in acidic solutions. The pH values at which the WSNGs begin to precipitate decreased as the molecular size of the WSNGs was lowered. WSNG3, which possesses a moderate molecular size among the WSNGs, adsorbed more 2-naphthol from acidic solutions than from neutral solutions. The maximum uptake of 2-naphthol on WSNG3 at the saturated concentration was, however, independent of the pH, both resulting in 1.28 mmolg(-1). This quantity indicates that each WSNG3 molecule adsorbs one and one-half 2-naphthol molecules. The maximum uptake was much greater than that of the graphitized carbon black (BET surface area, 77 m(2)g(-1)) and was equal to that of Amberlite XAD-2 (334 m(2)g(-1)). An increase in the molecular size of the WSNGs enhanced the adsorbate-adsorbent interaction, but decreased the maximum uptake of 2-naphthol at the saturated concentration.

Novel synthesis of polymer and carbonaceous nanomaterials via a micelle/silicate nanostructured precursor.

Mesoporous carbonaceous materials with relatively high surface area have been synthesized by a new method composed of in situ polymerization of divinylbenzene in the hydrophobic phase of a hexagonally arrayed micelle/silicate nanocomposite and subsequent carbonization and hydrofluoric acid treatments, while rod-like carbons were obtained from a direct incorporation of divinylbenzene into the mesopores of MCM-41.