Tunable Polyaniline‐Based Porous Carbon with Ultrahigh Surface Area for CO₂ Capture at Elevated Pressure

Abstract

Natural gas is the cleanest fossil fuel source. However, natural gas wells typically contain considerable amounts of CO 2 , with on‐site CO 2 capture necessary. Solid sorbents are advantageous over traditional amine scrubbing due to their relatively low regeneration energies and non‐corrosive nature. However, it remains a challenge to improve the sorbent's CO 2 capacity at elevated pressures relevant to natural gas purification. Here, the synthesis of porous carbons derived from a 3D hierarchical nanostructured polymer hydrogel, with simple and effective tunability over the pore size distribution is reported. The optimized surface area reaches 4196 m 2 g −1 , which is among the highest of carbon‐based materials, with abundant micro‐ and narrow mesopores (2.03 cm 3 g −1 with d < 4 nm). This carbon exhibits a record‐high CO 2 capacity among reported carbons at elevated pressure (i.e., 28.3 mmol g −1 total adsorption at 25 °C and 30 bar). This carbon also shows good CO 2 /CH 4 selectivity and excellent cyclability. Molecular simulations suggest increased CO 2 density in micro‐ and narrow mesopores at high pressures. This is consistent with the observation that these pores are mainly responsible for the material's high‐pressure CO 2 capacity. This work provides insights into material design and further development for CO 2 capture from natural gas.