Role of Benzyl Alcohol in Controlling the Growth of TiO₂ on Carbon Nanotubes

Molecular dynamics simulation has been used to investigate the role of benzyl alcohol (BA) in the morphological control of the growth of TiO ₂ on carbon nanotubes (CNTs) by the consideration of two model systems. First, the interface between graphene and BA, where we found that the adsorption layer is dominated by molecules lying parallel to the surface confirming the hypothesis that the phenyl ring in BA is able to undergo π-π stacking with the CNT. Second, simulation of the interface between BA and the most stable surfaces of rutile and anatase revealed that the phenyl ring favors an orientation parallel to the (110) surface of rutile, while at anatase surfaces, particularly (100), the ring is generally orientated perpendicular to the surface. We therefore propose that the mechanism by which CNTs are found experimentally to selectively template rutile nanotubes is due to noncovalent functionalization by BA, which subsequently induces the nucleation of a rutile structure via the interaction of hydroxyl groups with TiO₂.