Adsorption properties of templated nanoporous carbons consisting of 1-2 graphene layers

Abstract

A variety of vapor adsorption (water, methanol, ethanol, dichloromethane, and n -hexane) is examined on templated nanoporous carbons consisting of 1-2 graphene layers including microporous zeolite-templated carbon (ZTC), mesoporous carbon mesosponge (CMS) and graphene mesosponge (GMS). Conventional nanoporous carbon materials are used as references. While water-vapor adsorption is peculiar because of the repulsion between H 2 O molecules and hydrophobic carbon, organic-vapor adsorption basically follows the mechanism of typical physisorption. The graphene-based nanoporous materials exhibit a noticeable degree of adsorption-induced expansion from their extraordinary softness except the case of inferior water-vapor adsorption on mesoporous CMS and GMS. CMS exhibits an especially large degree of adsorption-induced expansion, and achieved very high adsorption capacities up to 4.25‒4.76 cm 3 g ‒1 for organic vapors, demonstrating its feasibility as a high-capacity adsorbent. The adsorption isotherms of ZTC at 278 K and 298 K for n -hexane are overlapping well, and it is advantageous for a new type of heat pump working with force-induced phase transition. Moreover, this work provides a general prediction of the ease of organic-vapor adsorption by the product of surface tension and molar volume.