DFT-Based Study for the Enhancement of CO 2 Adsorption on Metal-Doped Nitrogen-Enriched Polytriazines.

Nitrogen-enriched polytriazine (NPT), a carbon nitride-based material, has received much attention for CO 2 storage applications. However, to enhance the CO 2 uptake capacity more efficiently, it is necessary to understand the interaction mechanism between CO 2 molecules and NPT through appropriate modification of the structures. Here, we introduce a method to enhance the CO 2 adsorption capacity of NPT by incorporating metal atoms such as Sn, Co, and Ni into the polytriazine network. DFT calculations were used to investigate the CO 2 adsorption mechanism of the polytriazine frameworks by tracking the interactions between CO 2 and the various interaction sites of NPT. By optimizing the geometry of the pure and metal-containing NPT frameworks, we calculated the binding energy of metal atoms in the NPT framework, the adsorption energy of CO 2 molecules, and the charge transfer between CO 2 molecules and the corresponding adsorption systems. In this work, we demonstrate that the CO 2 adsorption capacity of NPT can be greatly enhanced by doping transition-metal atoms into the cavities of NPT.