Effects of diameter, length, chirality and defects on the scavenging action of single-walled carbon nanotubes for OH radicals: A quantum computational study

Abstract

Binding of an OH radical at the outer surfaces of the open-ended pristine armchair (5, 5), (7, 7) single-walled carbon nanotubes of varying lengths, zigzag (9, 0), (10, 0) tubes, and Stone-Wales and single vacancy defected (5, 5) tubes was investigated theoretically. Binding of two OH radicals with a zigzag (10, 0) nanotube was also investigated. The semiempirical PM6 method was used for geometry optimization which was followed by single-point energy calculations at B3LYP/6-31G(d,p) level of density functional theory. Binding energies of the adducts of armchair nanotubes with an OH radical each were found to decrease with increase in diameter, this effect being more pronounced for longer tubes. Semi-conducting zigzag (10, 0) tube was found to be a better OH radical scavenger than the metallic armchair (5, 5) and zigzag (9, 0) tubes. Stone-Wales and single vacancy defected armchair tubes were found to be less and more reactive respectively towards an OH radical than the corresponding pristine tubes. © 2010 Elsevier B.V. All rights reserved.