High Surface Area Nanoporous Carbon-Ceria Composites for CO₂ Capture and Enzyme-Mimicking Action

Nanoporous carbon-based composites with metal oxides have great potential for various applications including adsorption and sensing owing to their multiple properties. However, the fabrication of these nanocomposites without affecting these multiple properties is challenging. Herein, a series of nanoporous carbon-based nanocomposites with cerium nanoparticles are synthesized through a combination of high-temperature carbonization and ex-situ modification with cerium precursor. The prepared nanocomposites have appreciable surface areas, pore volumes, tunable pore sizes, and a controlled amount of surface nanoceria, all of which can be precisely controlled by varying the amount of KOH and cerium nitrate hexahydrate used for nanoceria generation. The porous carbon PC-3 was used for modification using nanoceria and the modified materials showed higher performance for the intended applications. The CO₂ adsorption per unit surface of PC-3 (2.4 μmol m^-2) increased to 2.9 μmol m^-2 in Ce-PC-3-0.5. Furthermore, the composite materials displayed higher heat of adsorption (Q_st) than bare materials, indicating stronger interactions with CO₂. Interestingly, the least amount of nanoceria (CePC-3-0.25) was effective in enhancing the superoxide dismutase (SOD) and catalase activity.