Surface ionic states and structure of titanate nanotubes

Abstract

Here we present an investigation on Zn-Ti-O ternary (zinc titanate) nanostructures which were prepared by a combination of electrospinning and atomic layer deposition. Depending on the ZnO and TiO2 molar ratio, two titanates and one mix phased compound were synthesized by varying the post-annealing temperatures. Specifically Zn2TiO4, ZnTiO3 and ZnO/TiO2 nanostructures were fabricated via thermal treatments (900, 700, 800 °C, respectively). Structural studies unveiled the titanate phase of the nanostructures. Furthermore, the ionic states of the titanate nanostructures on the surface are revealed to be Ti3+ and Zn2+. Spin-orbit splitting of Zn2p and Ti2p doublets were, however, not identical for all titanates which vary from 23.09-23.10 eV and 5.67-5.69 eV respectively. Oxygen vacancies were found on the surface of all titanates. The valance band region was analyzed for Zn3d, Ti3p, O2s and O2p and their hybridization, while the edge (below Fermi level) was determined to be at 2.14 eV, 2.00 eV and 1.99 eV for Zn2TiO4, ZnTiO3 and ZnO/TiO2 respectively.