Calcium-decorated carbon nanostructures for the selective capture of carbon dioxide.

The development of advanced materials for CO capture is of great importance for mitigating climate change. In this paper, we outline our discovery that calcium-decorated carbon nanostructures, i.e., zigzag graphene nanoribbons (ZGNRs), carbyne, and graphyne, have great potential for selective CO capture, as demonstrated via first-principles calculations. Our findings show that Ca-decorated ZGNRs can bind up to three CO molecules at each Ca atom site with an adsorption energy of ∼-0.8 eV per CO, making them suitable for reversible CO capture. They adsorb CO molecules preferentially, compared with other gas molecules such as H, N, and CH. Moreover, based on equilibrium thermodynamical simulations, we confirm that Ca-decorated ZGNRs can capture CO selectively from a gas mixture with a capacity of ∼4.5 mmol g under ambient conditions. Similar results have been found in other carbon nanomaterials, indicating the generality of carbon based nanostructures for selective CO capture under ambient conditions.