Improving CO₂capture in porous 3D-graphene by cationic nitrogen doping

Abstract

The highly porous three-dimensional (3D) graphene is a promising solid sorbent for carbon capture and storage. However, generally, the selectivity of a carbon-based sorbent for CO 2 in a gas mixture (such as the post-combustion flue gas in a power plant) is only moderate (∼10-20), which limits its applications. Here, using the Grand Canonical Monte Carlo (GCMC) simulation, we investigate a new type of nitrogen doping (N-doping) in graphene that contains cationic nitrogen sites for CO 2 adsorption. We found that due to the favorable electrostatic interaction both CO 2 adsorption and selectivity are improved substantially for the porous 3D graphene with the cationic N-doping and are at least an order of magnitude higher than those for the ones without N-doping or with neutral N-doping (such as graphitic, pyridinic, and pyrrolic ones). Our results highlight the possibility for this modified porous 3D graphene to possess both high selectivity and large adsorption for carbon capture, enhancing its commercial viability.