The evolvement of pits and dislocations on TiO2-B nanowires via oriented attachment growth

TiO2-B nanowires were synthesized by an ion exchanging-thermal treatment. The unique morphology of pits and dislocations interspersed on TiO2-B nanowires were firstly characterized and studied by high-resolution transmission electron microscopy (HRTEM). Oriented attachment is suggested as an important growth mechanism in the evolvement of pits and dislocations on TiO2-B nanowires. Lattice shears and fractures were originally formed during the ion exchanging process of the sodium titanate nanowires, which resulted in the formation of primary crystalline units and vacancies in the layered hydrogen titanate nanowires. Then the (110) lattice planes of TiO2-B grown in [110] direction is faster than the other lattice planes, which caused the exhibition of long dislocations on TiO2-B nanowires. The enlargement of the vacancies, which was caused by the rearrangement of primary crystalline units, should be the reason of the formation of pits. Additionally, the transformation from TiO2-B to anatase could be also elucidated by oriented attachment mechanism. (C) 2009 Elsevier Inc. All rights reserved.