Nanoconfinement‐Driven Energy‐Efficient CO 2 Capture and Release at High Pressures on a Unique Large‐Pore Mesoporous Carbon

Abstract Although microporous carbons can perform well for CO 2 separations under high pressure conditions, their energy‐demanding regeneration may render them a less attractive material option. Here, we developed a large‐pore mesoporous carbon with pore sizes centered around 20–30 nm using a templated technical lignin. During the soft‐templating process, unique cylindrical supramolecular assemblies form from the copolymer template. This peculiar nanostructuring takes place due to the presence of polyethylene glycol (PEG) segments on both the Pluronic® template and the PEG‐grafted lignin derivative (glycol lignin). A large increase in CO 2 uptake occurs on the resulting large‐pore mesoporous carbon at 270 K close to the saturation pressure (3.2 MPa), owing to capillary condensation. This phenomenon enables a CO 2 /CH 4 selectivity ( S CO2/CH4 , mol/mol) of 3.7 at 270 K and 3.1 MPa absolute pressure, and a swift pressure swing regeneration process with desorbed CO 2 per unit pressure far outperforming a benchmark activated carbon ( i.e ., notably rapid decrease in the amount of adsorbed CO 2 with decreasing pressure). We propose large‐pore mesoporous carbons as a novel family of CO 2 capture adsorbents, based on the phase‐transition behavior shift of CO 2 in the nanoconfined environment. This novel material concept may open new horizons for physisorptive CO 2 separations with energy‐efficient regeneration options.