Synthesis of a novel porous material comprising carbon/alumina composite aerogels monoliths with high compressive strength

Resorcinol–formaldehyde/alumina composite (RF/Al2O3) gels were initially prepared by using sol–gel techniques, and then dried to aerogels with supercritical fluid CO2. After thermal treatment in argon atmosphere, RF/Al2O3 aerogels were successfully converted to monolithic carbon/alumina composite (C/Al2O3) aerogels. The samples were characterized by BET, SEM, TEM and XRD, and the compressive strengths were measured. The experimental results showed that the C/Al2O3 aerogels exhibited an interpenetrating framework with high mesoporosity. The as-synthesized C/Al2O3 aerogels consisted of spherical carbon particles and alumina (fibrous or columnar), which had high BET surface area (576–831 m2/g) and showed high compressive strength (5.4–9.1 MPa) and Young’s modulus (286.95–476.71 MPa). These novel C/Al2O3 aerogels could possibly be used as thermal isolates, catalysts and adsorbents.

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► A simple route was used to synthesize the RF/Al2O3 aerogels (sol–gel, RT).
► High surface area of 831 m2/g was achieved after thermal treatment of 1400 °C/5 h.
► Sample exhibited high compressive strength and Young’s modulus (9.1 and 476.7 MPa).
► The C/Al2O3 aerogels had high-temperature resistance properties.