Process for preparing a carbon foam and use of the material obtained

A process for preparing a porous carbon material, wherein said method comprises at least one step of heat treatment at a temperature of at least 300° C., under a nonoxidizing atmosphere, of an organic molecule selected from the oxocarbons and oxocarbon derivatives of formulae (I-1) to (I-7) below:

• in which:
• R1 to R8, R13 to R21, and R24, independently of one another, represent OH;
• SH;
• an O-alkyl or S-alkyl group in which the alkyl radical is linear and has from 1 to 4 carbon atoms;
• an O-aryl or S-aryl group in which the aryl ring is a phenyl ring or a phenyl ring substituted in para position by an O-methyl or S-methyl group;
• or a group NR25R26 in which the radicals R25 and R26, which are identical or different, represent a C1-C4 alkyl radical;
• R9 to R12 and R22 and R23, independently of one another, represent an oxygen or sulfur atom;
• an N—CN (isocyano) group;
• or a C(CN)2 (malononitrile) group.