Effect of N-Containing Functional Groups on CO2 Adsorption of Carbonaceous Materials: A Density Functional Theory Approach

详细信息    查看全文

• 作者：Geunsik Lim ; Ki Bong Lee ; Hyung Chul Ham
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：April 21, 2016
• 年：2016
• 卷：120
• 期：15
• 页码：8087-8095
• 全文大小：543K
• 年卷期：0
• ISSN：1932-7455

文摘

The amount of anthropogenic CO₂ emission keeps increasing worldwide, and it urges the development of efficient CO₂ capture technologies. Among various CO₂ capture methods, adsorption is receiving more interest, and carbonaceous materials are considered good CO₂ adsorbents. There have been many studies of N-containing carbon materials that have enhanced surface interaction with CO₂; however, various N-containing functional groups existing in the carbon surface have not been investigated in detail. In this study, first-principle calculations were conducted for carbon models having various N-functional groups to distinguish N-containing heterogeneity and understand carbon surface chemistry for CO₂ adsorption. Among N-functional groups tested, the highest adsorption energies of −0.224 and −0.218 eV were observed in pyridone and pyridine groups, respectively. Structural parameters including bond angle and length revealed an exceptional hydrogen-bonding interaction between CO₂ and pyridone group. Charge accumulation on CO₂ during interaction with pyridine-functionalized surface was confirmed by Bader charge analysis. Also, the peak shift of CO₂ near Fermi level in the DOS calculation and the presence of HOMO on pyridinic-N in the frontier orbital calculation determined that the interaction of pyridinic-N is weak Lewis acid–base interaction by charge transfer. Furthermore, adsorption energies of N₂ were calculated and compared to those of CO₂ to find its selective adsorption ability. Our results suggest that pyridone and pyridine groups are most effective for enhancing the interaction with CO₂ and have potential for selective CO₂ adsorption.