Abstract

Mesoporous carbon materials (pore size ranging 2-50 nm) have been used in applications as membranes, filters, catalyst supports or electrodes in electrochemical devices. Their problems related with diffusion of reactants/products and heat leading off from or supplied to the reactors have motivated the efforts directed to obtain new materials capable of combining pores in different scales. In this work a double templating method is used to generate carbon foams with hierarchical pore structure. The mixture of mesophase pitch (MP) and polystyrene (PS) allows infiltrating preforms of packed NaCl particles which afterwards can be removed away by dissolution in water, forming the large pores in the material. Posterior heat treatments allow removing an interconnected fine microstructure created by the PS, which is able to create the fine porosity in the material. The success of the process depends on the solidification conditions of the infiltrating mixture and the careful removal of the templates. By this method a new class of materials with hierarchical porosity (pores in the range 500 mm-20 nm) has been obtained.