Polar graphene for point-source carbon capture

The world is facing a climate crisis resulting primarily from overabundance of carbon dioxide in the atmosphere. Much of that comes from power plants burning fossil fuels, and one short-term solution to eliminate most of their emissions is to capture the carbon dioxide at the source. Any sorbent capable of doing this would need to be highly attractive to CO₂ as well as selective to exclude other gases. Ideally, such a sorbent would also be cheap and made of readily available materials.

Luan et al. detail a process to improve the adsorption and selectivity of one such sorbent: porous 3D graphene. By implementing cationic nitrogen doping, they created a highly polar environment that is much more attractive to CO₂ while excluding other gases like nitrogen.

“Carbon-based solid sorbents for CO₂ capture are abundant, cheap, sustainable and environmentally friendly,” said author Daniel Luan. “However, general carbon-based sorbents are not polar enough, so their selectivity for CO₂ is moderate. In this work, we proposed a new carbon-based sorbent that overcomes this shortcoming.”

Cationic nitrogen doping was recently developed for graphene, and unlike other forms of nitrogen doping it was found to significantly increase the material’s polarity. Using a Monte Carlo simulation, the authors demonstrated that this increased polarity resulted in at least an order of magnitude increase in the adsorption and selectivity for CO₂, putting it within the range for point-source carbon capture.

The researchers plan to expand their results with more detailed simulations and additional materials, which could inspire experimentalists to carry out relevant work.

“Our goal is to keep improving both the CO₂ loading and the CO₂ selectivity for solid sorbents with rational and novel designs,” said Luan.

Source: “Improving CO₂ capture in porous 3D-graphene by cationic nitrogen doping,” by Daniel Luan, Victor Zhou, Nianjun Zhou, and Binquan Luan, Journal of Applied Physics (2022). The article can be accessed at https://doi.org/10.1063/5.0129554 .