Adsorption of diatomic molecules on graphene, h-BN and their BNC heterostructures: DFT study

Abstract

Physical adsorption of three diatomic molecules (H2, CO, and HCl) on graphene, hexagonal boron nitride (h-BN), and two heterostructures, mBNC (h-BN ring is surrounded by carbon atoms), and pBNC (carbon ring is surrounded by boron and nitrogen atoms), was studied by using density functional theory (DFT) and independent gradient model (IGM) calculations to reveal peculiarities of their non-covalent interactions. Adsorption of hydrogen molecules shows approximately equal adsorption energies (Ea) of ca.−1 kcal/mol for both graphene and heterostructures, whereas adsorption on h-BN is less favorable. On the other hand, the CO molecule when adsorbed on pBNC exhibits much higher Ea (−3.43 kcal/mol) in comparison with other studied adsorbents, and the excess reaches 26% for the case of h-BN. The pBNC heterostructure also shows the increased Ea of −5.87 kcal/mol for the HCl molecule. Compared with mBNC, the excess achieves 33%. The present work, which observes representative model systems, can propose a simple way of describing the complicated events that occur in interfacial regions of BNC adsorbents.