Synthesis, characterization and gas sorption properties of a molecularly-derived graphite oxide-like foam A.B. Bourlinos a, * , Th. A. Steriotis b , M. Karakassides c , Y. Sanakis a , V. Tzitzios a , C. Trapalis a , E. Kouvelos b , A. Stubos d a Institute of Materials Science, NCSR ‘‘Demokritos’’, Ag. Paraskevi Attikis, Athens 15310, Greece b Institute of Physical Chemistry, NCSR ‘‘Demokritos’’, Ag. Paraskevi Attikis, Athens 15310, Greece c Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina, Greece d Institute of Nuclear Technology and Radiation Protection, Environmental Research Laboratory, NCSR ‘‘Demokritos’’, Ag. Paraskevi Attikis, Athens 15310, Greece Received 30 July 2006; accepted 8 November 2006 Available online 18 December 2006 Abstract Calcination of the molecular precursor sodium chloranilate dihydrate at 300 °C in air leads to a foam-type graphite oxide-like deriv- ative that is lightweight, has a high surface area and porosity, and contains oxygen in the concentration range of conventional graphite oxide. Characterization with a variety of techniques revealed that the porous network consists of interconnected bundles (crystallites) of turbostratically stacked graphene layers built up of aromatic and aliphatic domains and with polar hydrophilic groups pending on the outer surface. The EPR study unveiled an unusually high spin concentration that possibly endows the material with extra functionalities/ reactivity. The foam selectively absorbs CO 2 but shows a low adsorption capacity towards N 2 , CH 4 and H 2 gases. The material strongly sorbs CO in the absence of metal catalysts. Ó 2006 Elsevier Ltd. All rights reserved. 1. Introduction Graphite oxide is an oxygen-rich carbogenic material that is typically derived by strong oxidation of crystalline graphite and contains oxygen in the concentration range 30–40% w/w. The functional solid exhibits an extended lamellar structure with randomly distributed aromatic and aliphatic regions, as well as, a high amount of hydro- xyl/carboxyl functional groups embedded on its layers. Accordingly, graphite oxide is endowed with interesting swelling, intercalation and ion exchange properties that enable the design and engineering processing of valuable reconstructed derivatives and thin films [1–6]. In addition to these properties, the layered solid also exhibits a remark- able thermal behaviour: it easily decomposes at relatively low temperature (<200 °C) by releasing CO 2 and H 2 O to afford lightweight carbogenic soot [7,8]. Although the carb- ogenic soot lacks the colloidal properties of traditional graphite oxide, however, it still has a layered structure (i.e. bundles of graphene layers with d 002 = 0.4 nm), it con- tains a residual amount of oxygen mainly at the periphery of the layers (5–10% w/w) and it is built up of aromatic (sp 2 -hybridized carbon) and aliphatic domains (sp 3 -hybrid- ized carbon), similarly to conventional graphite oxide. As such, the lightweight graphite oxide-like derivative repre- sents an alternative engineering form that holds promise in a range of important applications, including lithium bat- teries, insulators and absorbents [7,8]. Nevertheless, the small surface area of the lightweight product (<50 m 2 g 1 ) imposed by the large lateral dimensions of the graphite oxide precursor (>1 lm) combined with its low oxygen content, which provides binding sites to the surface, limits further potential uses. 0008-6223/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2006.11.008 * Corresponding author. Fax: +30 11 30 210 6519430. E-mail address: bourlinos@ims.demokritos.gr (A.B. Bourlinos). www.elsevier.com/locate/carbon Carbon 45 (2007) 852–857