Preparation of hierarchical porous carbonaceous foams from Kraft black liquor

Kraft black liquor, an cheap and widely available biomass by-product, has been emulsified with 1,2-dichloroethane, and then crosslinked by epichlorohydrin to prepare rigid macroporous bio-based monoliths. A subsequent thermal treatment under nitrogen of these materials produces carbon foams or carboHIPEs, with hierarchical porosity: the original macroporous structure is preserved while mesopores and micropores structuring the walls are created. Specific surface areas of 500–1000 m2 .g–1 and micropore volumes of 0.3–0.5 cm3 .g– 1 can be obtained. In addition, after a further thermal treatment at higher temperature, these new carboHIPEs show an exceptionally high electrical conductivity over 800 S. m–1. Therefore, they may find applications in the field of energy storage.