Journal of Microscopy, Vol. 246, Pt 3 2012, pp. 274–278 doi: 10.1111/j.1365-2818.2012.03615.x Received 14 October 2011; accepted 7 March 2012 A direct and quantitative image of the internal nanostructure of nonordered porous monolithic carbon using FIB nanotomography J. BALACH ∗ , F. MIGUEL †, F. SOLDERA †, D.F. ACEVEDO ∗ , F. M ¨ UCKLICH † & C.A. BARBERO ∗ ∗ Programa de Materiales Avanzados, Universidad Nacional de R´ ıo Cuarto, Agencia Postal No 3, 5800 R´ ıo Cuarto, Argentina †Department Materials Science, Saarland University, Campus D3.3, 66123 Saarbr ¨ ucken, Germany Key words. Carbon, focused ion beam, mesopore, nanotomography. Summary A direct study of the shape, size and connectivity of nonordered pores in carbon materials is particularly challenging. A new method that allows direct three-dimensional (3D) investigations of mesopores in monolithic carbon materials and quantitative characterization of their physical properties (surface area and pore size distribution) is reported. Focused ion beam (FIB) nanotomography technique is performed by combination of focused ion beam and scanning electron microscope. Porous monolithic carbon is produced by carbonization of a resorcinol-formaldehyde gel in the presence of a cationic polyelectrolyte as a pore stabilizer. Introduction Porous carbon materials have a wide range of technological applications (Kinoshita, 1998; Burchell, 1999). Important parameters for such materials are the size and the distribution of pores, as well as the specific surface area. While some methods, such as gas adsorption isotherms and mercury porosimetry, give information on the amount of surface area and/or the mean size of pores, a detailed three-dimensional (3D) image of the porous materials is not provided by those techniques. In the case of ordered porous materials, diffraction techniques like small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) and/or transmission electron microscopy could give a picture of the typical pores. However, disordered porous carbon, including activated carbon (Bansal, 2005), which is a quite common material, cannot be characterized properly using those techniques. A detailed 3D picture of the pore size, distribution and connectivity is necessary to assess the usefulness of carbon materials for technological applications. Such measurements Correspondence to: C.A. Barbero. Chemistry Department, National University of Rio Cuarto, Rio Cuarto, Argentina. Tel: +54 358 4676157; fax: +54 358 4676233; e-mail: cbarbero@exa.unrc.edu.ar can only be obtained by electron tomography techniques, because the resolution of X-ray computer tomography, even in a synchrotron, is not good enough to resolve the nm-sized pores. Recently, Ziegler et al. (Ziegler, Thiele & Zengerle, 2011) demonstrated the capabilities of focused ion beam nanotomography (FIB-nt) technique to visualize the 3D morphology of a porous carbon-based catalyst support material. Even though quantitative analyses were made (total porosity and pore size distribution), no additional technique was used to validate those results. In this contribution, FIB-nt will be employed not only to obtain a visual 3D morphology representation of disordered nanoporous carbon, but also to characterize in detail their structural parameters such as: specific surface area, pore size distribution, total porosity and connectivity of pores. The results will be compared to measurements done with nitrogen sorption isotherm method, in which the specific surface area and the pore size distribution of the same sample were determined (Bruno et al., 2010). Given that the porous structure of synthetic disordered porous carbons, like carbon aerogels (Moreno-Castilla & Maldonado-H´ odar, 2005), can be controlled from synthetic conditions (Bruno et al., 2010), the studies of the porosity and connectivity of the pores via characterizations using FIB-nt measurement would allow the choice of the best carbon material for technological applications, such as electric double layer supercapacitors, fuel cell electrodes, lithium batteries and catalyst support. Materials and methods Synthesis of porous monolithic carbon Precursor gels were synthesized by sol-gel polycondensation of resorcinol (R) with formaldehyde (F) in the presence of polyelectrolyte. In this study, sodium carbonate (C) and cationic polyelectrolyte, poly(diallyl,dimethyammonium) chloride (PDADMAC), were used as a basic catalyst and a C  2012 The Authors Journal of Microscopy C  2012 Royal Microscopical Society