Density Functional Study of Interaction of Atomic Pt with Pristine and Stone−Wales-Defective Single-Walled Boron Nitride Nanotubes

Abstract

Interactions between atomic Pt and pristine or Stone−Wales-defective (5,5) single-walled boron nitride nanotubes (BNNTs) were studied using density functional theory (DFT) with truncated nanotube models. The binding energy of Pt on a pristine BNNT is about 20 kcal/mol with little dependency on the binding site. On the other hand, when the Stone−Wales (SW) defect is presented, the atomic Pt is preferentially inserted between the B−B bond in the SW defect region with a large binding energy of 58 kcal/mol. On an SW-defective BNNT, the atomic Pt, even placed away from the defect site, may eventually (thermodynamically) move toward the defect area until being trapped between the B−B bond, and the final adduct has decreased reactivity toward both electrophiles and nucleophiles compared with Pt adsorption to pristine BNNTs. Pt adsorption on pure or SW-defective BNNTs makes the hosting nanotube wide-gap semiconductive by introducing the valence states of the absorbed Pt into the band gap of the nanotube. In comparison, the Pt atom filling into a B or N single vacancy on a BNNT changes the electronic structure of the vacancy-defective BNNT so dramatically that the Pt-doped BNNT becomes semiconducting with improved reactivity.