π-π interactions between benzene and graphene by means of large-scale DFT-D4 calculations

The adsorption of aromatic molecules on graphene is essential for many applications. This study addresses the issues associated with predicting accurate binding energies between graphene and benzene using a series of increasingly larger nanographene (C24H12, C54H18, C96H24, C150H30, and C216H36). For this purpose, we consider several DFT methods developed for accurately predicting noncovalent interactions, namely, PBE0-D4, omega B97X-D4, PW6B95-D4, and MN15. The C150H30 and C216H36 nanographene predict binding energies converged to sub-kJ mol(-1) with respect to the size of the nanographene. For the largest C216H36 nanographene, we obtain binding energies of -37.9 (MN15), -39.7 (omega B97X-D4), -40.7 (PW6B95-D4), and -49.1 (PBE0-D4) kJ mol(-1). Averaging these values, we obtain Delta E-e,E-bind = -41.8 +/- 8.6 kJ mol(-1), which translates to Delta H-0,H-bind = -41.0 +/- 8.6 kJ mol(-1). This theoretical binding energy agrees with the experimental value of -48.2 +/- 7.7 kJ/mol within overlapping uncertainties.

Automated summary

This study predicts the binding energies between graphene and benzene by using different sizes of nanographene. The results show that the predicted binding energies converge as the size of nanographene increases. The binding energy of the largest nanographene C216H36 agrees with the experimental value.