Effect of template constraints on adsorption properties of synthetic carbons prepared within the gallery of layered double hydroxides

Mg-Al layered double hydroxides have been synthesized and 1,5-naphthalene disulfonate dianions have been intercalated; the organic molecules were carbonized within the layered framework. For comparison, a reference carbon was prepared from the sodium salt of the 1,5-naphthalene disulfonic acid precursor using conventional carbonization under the same thermal and post-treatment conditions. The surface properties of the carbonized product extracted from the carbon-mixed oxide nanocomposite have been studied by adsorption techniques and the results compared to the adsorption characteristics of the reference carbon. The sorption of nitrogen at 77 K and carbon dioxide at 298 K demonstrate that, although the two carbons have almost the same specific surface area and total pore volumes, there is a significant difference in their micropore structure. Micropore size distributions calculated from adsorption isotherms of methane and sulfur hexafluoride at near ambient temperatures reveal a more heterogeneous micropore structure for the template derived carbon compared to the reference. The factors controlling micropore structure development during two-dimensional carbonization are discussed based on DTA, results of sorption of carbon dioxide and FTIR spectroscopic measurements. Copyright (C) 1996 Elsevier Science Ltd