Department of Chemistry and Physics, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
Int J Mol Sci. 2023 Jul 14;24(14):11452. doi: 10.3390/ijms241411452.
Concerns regarding the environmental impact of increasing levels of anthropogenic carbon dioxide have led to a variety of studies examining solid surfaces for their ability to trap this greenhouse gas (GHG). Atmospheric or post-combustion carbon capture requires an efficient separation of carbon dioxide and nitrogen gas. We used the molecular mechanics MM3 parameter set (previously shown to provide good estimates of molecule-surface binding energies) to calculate theoretical surface binding energies for carbon dioxide ∆E(CO) and nitrogen ∆E(N). For efficient separation, differentiation of these two gas-surface adsorption energies is required. Examined structures based on graphene, carbon slit width pore, and carbon nanotube gave ∆E(CO) to ∆E(N) ratios of 1.7, 1.8, and 1.9, respectively. To enhance the CO adsorption, we developed a model graphene surface pore lined with four hydroxy groups whose orientation allowed them to form hydrogen bonds with the oxygens in CO. Both the single-layer and double-layer versions of this pore gave significant enhancement in the ability to trap CO preferentially to N. The two-layer version of this pore gave ∆E(CO) = 73 and ∆E(N) = 6.8 kJ/mol. The one- and two-layer versions of this novel pore averaged a ∆E(CO) to ∆E(N) ratio of 12.
人们对不断增加的人为二氧化碳排放对环境造成的影响感到担忧，这促使人们开展了各种研究，以考察固体表面捕获这种温室气体（GHG）的能力。大气或燃烧后碳捕获需要有效地将二氧化碳和氮气分离。我们使用分子力学 MM3 参数集（先前已证明该参数集可很好地估算分子-表面结合能）来计算二氧化碳 ∆E(CO)和氮气 ∆E(N)的理论表面结合能。为了实现高效分离，需要区分这两种气体-表面吸附能。基于石墨烯、碳狭缝宽度孔和碳纳米管的研究结构分别给出了 ∆E(CO)与 ∆E(N)的比值为 1.7、1.8 和 1.9。为了增强 CO 的吸附，我们开发了一种模型石墨烯表面孔，其内部由四个羟基基团组成，这些基团的取向使其能够与 CO 中的氧形成氢键。这种孔的单层和双层版本均显著增强了优先捕获 CO 而不是 N 的能力。该孔的双层版本的 ∆E(CO)为 73kJ/mol，而 ∆E(N)为 6.8kJ/mol。这种新型孔的单层和双层版本的 ∆E(CO)与 ∆E(N)的平均值比为 12。
