Unique bimodal carbon xerogels from soft templating of tannin

Carbon xerogels were prepared by soft templating of tannin-formaldehyde resin as the precursor and F-127 Pluronic (R) used as both surfactant and templating agent. The influence of preparation pH and amount of Pluronic was systematically investigated, and the resultant porous structures were analysed by mercury porosimetry, helium and envelope pycnometry, and nitrogen adsorption. We show how highly controlled structures can be obtained, presenting bimodal character - either macro-microporous or meso-microporous - and mostly having very narrow pore-size distributions. The corresponding carbon gels have disordered but quite well calibrated and available porosity, with pore volumes and surface areas typical of far more expensive carbon aerogels. They might be used in any application requiring an excellent availability of microporosity and/or mesoporosity. (C) 2014 Elsevier B.V. All rights reserved.