Adsorption properties of templated nanoporous carbons comprising 1–2 graphene layers
Hirotomo Nishihara, Hongwei Zhao, Kazuya Kanamaru, Keita Nomura, Mao Ohwada, Masashi Ito, Lixiang Li, Baigang An, Toshihide Horikawa, Takashi Kyotani
Abstract
Various types of vapor adsorption (water, methanol, ethanol, dichloromethane, and n-hexane) were examined on templated nanoporous carbons comprising 1–2 graphene layers, e.g., microporous zeolite-templated carbon (ZTC), mesoporous carbon mesosponge (CMS), and graphene mesosponge (GMS). Conventional nanoporous carbon materials are used as references. Although water-vapor adsorption is unique owing to the repulsion between H2O molecules and hydrophobic carbon, organic-vapor adsorption follows a typical physisorption mechanism. Graphene-based nanoporous materials exhibit an evident degree of adsorption-induced expansion based on their extraordinary softness, except in the case of inferior water-vapor adsorption on mesoporous CMS and GMS. CMS exhibits a considerable degree of adsorption-induced expansion and can achieve high adsorption capacities up to 4.25–4.76 cm3 g−1 for organic vapors, demonstrating its feasibility as a high-capacity adsorbent. The adsorption isotherms of ZTC at 278 and 298 K for n-hexane overlap well, which is advantageous for a new heat pump working with a force-induced phase transition. Moreover, this study helps predict the ease of organic-vapor adsorption based on the product of the surface tension and molar volume.