Adsorption of strategic gases on modified nanoporous carbons

The capture and storage of gases like CO₂, CH₄, and H₂ are key to mitigating climate change and advancing alternative sustainable energies. Adsorption has emerged as an effective strategy, with nanoporous carbons (NPC) being promising adsorbents due to their low cost and availability, high surface area, micro- and mesoporosity, thermal stability, and the ability to modify their surface. This study investigated CMK-8 and CMK-9 NPCs, synthesized via nanocasting and modified with nitric acid and 3-aminopropyltriethoxysilane (APTES). Textural, thermal, and surface properties were analyzed, and adsorption capacities for CO₂ (308 K), CH₄ (298 K), and H₂ (77 K) were evaluated (P ≤ 10 bar). Simulations helped understand the mechanisms of influence of functional groups. Pristine carbons were found to have specific surface areas of 870–1130 m²/g and pore volumes of 0.80 cm³/g, with micropores (~1.5 nm) and mesopores (~4.5 nm). Chemical modification (mainly with APTES) reduced surface properties and adsorption capacity by over 20%. Despite this, modified materials exhibited adsorption capacities equal to or greater than other carbon-based adsorbents, highlighting their potential for gas capture.