Stability of TiO_2 Molecule Confined Inside a Carbon Nanotube: A Theoretical Study

摘要

DFT calculations show that TiO_2 molecule is able to be confined inside single walled carbon nano- tubes. Depending on the diameter size, three behaviors were identified. Inside the tubes of diameters less than 5.6 ?, Titanium and Oxygen atoms interact chemically with the carbon walls of the tube and hyper-valences were observed. For tubes with diameters greater than 7.051 ?, TiO_2 molecule exits the nanotube. The studied molecule remains confined without altering its geometry in nanotubes with diameters between these two limits. TiO_2 molecule confined in the nanotube (5,5) of diameter 6.785 ? is stabilized by an energy of - 83.646 kcal mol~(-1) caused by weak interactions established with the nanotube. Our calculations show that the confinement of TiO_2 in nanotubes with adequate diameter allows the isolation of this molecule at room temperature while it was actually synthesized only in rare gas matrices at very low temperatures.