Epitaxial Growth Route to Crystalline TiO2 Nanobelts with Optimizable Electrochemical Performance

Anatase TiO2 nanobelts with 13 nm in thickness have been successfully synthesized via an epitaxial growth chemical transformation, in which the primary H2Ti3O7 nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory (Na2Ti3O7 and H2Ti3O7) and resultant products (TiO2) are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the TiO2 nanobelts indicates epitaxial nucleation and oriented growth of textured TiO2 inside the nanobelts. TiO2 nanocrystals prefer certain epitaxial growth direction due to the structural matching of (110)H2Ti3O7//(101)TiO2. We demonstrated that the initial reversible capacity of these TiO2 nanobelts attained 225 mA h/g. Furthermore, the nanobelts exhibit high power density along with excellent cycling stability in their application as hybrid electrochemical cells.