Binding of Single and Double Methane with Aromatic Hydrocarbons and Graphene

Graduate #42
Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science

Jovian Lazare - Clark Atlanta University
Co-Author(s): Dalia Daggag, Clark Atlanta University, Atlnata, GA; Dr. Tandabany Dinadayalane, Clark Atlanta University, Atlanta, GA

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Detailed computational investigations on the binding of methane with a range of materials are crucial to develop efficient molecular systems for methane sensor or storage applications [1, 2]. Density functional theory (DFT) calculations were performed to understand the binding of one and two methane molecules with smaller cyclic/polycyclic aromatic hydrocarbons (benzene, pyrene, and coronene). Our investigation also includes small and large size graphene systems consisting of 62 and 186 carbon atoms, respectively. All the molecular systems considered here offer two sides for binding of more than one methane molecule. Our detailed computational study is aimed to obtain knowledge on how binding energies and binding distances change while moving from small system to large as well as the selectivity of the side for the binding of second methane. Full geometry optimizations were performed using M06-2X/6-31G(d) level. Binding energies were calculated with and without Basis Set Superposition Error (BSSE) correction. The HOMO-LUMO energy gaps were calculated at the TPSSh/6-31G(d) level using M06-2X/6-31G(d) optimized geometries and they show interesting trends. In this study, different binding modes that include three, two and one C-H of methane were considered for binding with pi-molecular systems. In case of two methane molecules, we explored the options of binding on the same and opposite sides of the plane of pyrene, coronene, and graphene systems. Our results reveal that methane molecules prefer three C-H to bind with large pi-systems to produce the most stable complex. Binding strength increases marginally when we move from pyrene to coronene then to graphene. As the number of methane molecules increases from one to two, the binding energy is almost doubled in most cases. Interestingly, two methane molecules prefer to bind on the same side rather than opposite sides of coronene, small graphene, and large graphene systems. This may be due to stabilizing CH…HC interactions between two methane molecules on the surface of the pi-systems. References: (1) Wu Z, Chen X, Zhu S, Zhou Z, Yao Y, Quan W, et al. Room temperature methane sensor based on graphene nanosheets/polyaniline nanocomposite thin film. IEEE Sens J., 2013, 13, 777–782; (2) Hill, E. W.; Vijayaragahvan, A.; Novoselov, K. S. Graphene Sensors. IEEE Sens. J., 2011, 11, 3161−3170.

Jovian-ERN-abstract.docx

Funder Acknowledgement(s): We thank the National Science Foundation (NSF) for the financial support through HBCU-UP Research Initiation Award (Grant number 1601071). Extreme Science and Engineering Discovery Environment (XSEDE) is acknowledged for the computational resources.

Faculty Advisor: Dr. Tandabany Dinadayalane, dtandabany@cau.edu

Role: Completed all the calculations. Completed 80 percent of the analysis. Prepared 1st version of the abstract.