First-principle investigation of thiophene adsorption on TM (Ni/Co/Mn)-doped (ZnO)15 nanotube

The adsorption of thiophene on transition metal (Ni/Co/Mn)-doped (ZnO)(15) nanotube is investigated using density functional theory calculation. Different adsorption possibilities have been investigated. It is found that the stability of the nanotube increases with the doping of the transition metal (Ni/Co/Mn) atom, and the doping of transition metal (Ni/Co/Mn) atom should be mainly responsible for the reduction of the energy gap. We also observed an elongation of the S-C bond in adsorbed thiophene in Ni/Co/Mn-doped (ZnO)(15) adsorption systems, compared with those of adsorbed thiophene in pristine (ZnO)(15) adsorption systems, illustrating the S C bonds in adsorbed thiophene are active by transition metal atom in Ni/Co/Mn-doped (ZnO)(15) nanotubes. Molecular orbital results show that pi-backdonation is found in eta(2) bonding mode. Moreover, compared with the vibrational frequencies of free thiophene, the nu(C=C)(sym) and nu(C-S)(as) bands of eta(2) bonding mode are shifted to lower wavenumber. (C) 2015 Elsevier B.V. All rights reserved.