(247x) Density Functional Theory Study of CO2 Adsorption on Surface-Modified Graphene with Nitrogen Heterogeneity

 Emission of carbon dioxide, during anthropogenic activities such as energy production from fossil fuels and usage of transportation, has been continuously increasing. Due to its detrimental effects to the ecosystem, researches for reducing carbon dioxide are being actively conducted. Among various capture technologies, adsorption is advantageous in terms of regenerability of adsorbents and high efficiency. Since capture takes more than 70% of the cost of carbon dioxide capture and storage (CCS) technology, highly efficient adsorbents are needed to be developed. In this respect, density functional theory (DFT) can be exploited to analyze adsorbents and understand the requirements for good adsorbents by confirming interaction of adsorbents with carbon dioxide in nanoscale. In this study, based on DFT, calculations for theoretical design of adsorbent have been conducted. Among many carbon-based adsorbents, graphene was chosen for study due to its high surface area and unique two dimensional structure. The effects of heteroatom dopant and functionalities, especially nitrogen, have been investigated. Geometry optimization followed by carbon dioxide binding energy calculation made it possible to compare various N functionalities and to confirm the positive effect of N doping. From our results, it is expected that the optimal conditions of the surface of adsorbents can be figured out to aid practical synthesis of adsorbents.