Porous carbon monoliths with pore sizes adjustable between 10 nm and 2 μm prepared by phase separation – New insights in the relation between synthesis composition and resulting structure

Abstract

Porous carbon monoliths with tunable porosity are promising materials for a variety of applications like energy storage and adsorption. But the synthesis of carbons with monolithic shape and controlled porosity is often time-consuming and expensive. Here, micro-/macroporous and micro-/mesoporous carbon monoliths were synthesized via a simple process of polymerization induced phase separation of resorcinol and formaldehyde followed by drying at ambient pressure and carbonization. The carbon monoliths are mechanically stable and exhibit specific surface areas between 390 and 1100 m2·g−1. The size of the macro- and mesopores can be tailored over a wide range from approximately 10 nm to 2 μm by simply altering the solvent composition during the synthesis of the organic monoliths. The influence of solvent composition and resorcinol concentration on the pore size in the carbon monoliths was investigated with a focus on the smaller pore sizes and an exponential relation was observed. Finally, selected monoliths were activated in a stream of CO2 to produce hierarchically porous monoliths with specific surface areas between 1000 and 2400 m2·g−1. The activated monoliths were characterized in terms of their CO2 adsorption and showed adsorption capacities of up to 3.10 mmol·g−1 at 298 K.