Exploring the adsorption behavior of N-octyl pyridinium ionic liquids on graphene: Insights into reactivity and stability

Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) are used in this work to examine the adsorption and interaction mechanisms of the N-octyl pyridinium cation (OP) on graphene. According to the adsorption energy analysis, the most stable configuration ($50.73\text{kcal/mol}$) with a Boltzmann probability greater than 99% is the G-OP-1 configuration, which is defined by a planar alignment of the alkyl chain with the graphene surface. In comparison to the isolated components, the G-OP-1 complex’s HOMO-LUMO energy gap ($6.23\text{kcal/mol}$) was considerably smaller, suggesting improved reactivity and effective electron transmission. While QTAIM showed 12 bond critical points (BCPs) compatible with weak electrostatic interactions sustained by van der Waals forces, Fukui function analysis discovered complimentary nucleophilic and electrophilic areas. These results highlight the potential of OP-functionalized graphene for use in electrochemical sensing and catalysis, laying the groundwork for the development of cutting-edge materials for environmental monitoring and energy storage.