Preparation of TiO2–(B) by microemulsion mediated hydrothermal method: effect of the precursor and its electrochemical performance

Synthesis of TiO 2 –(B) bronze was carried out by hydrothermal method using different precursors: (a) commercial anatase, (b) amorphous TiO 2 prepared by O/W microemulsion method and (c) oil-in-water (O/W) microemulsion with freshly prepared amorphous TiO 2 . It is important to highlight this is the first report of the preparation of TiO 2 –(B) using an O/W microemulsion as a precursor. The effect of precursor type on the resulting TiO 2 nanostructures, namely, their structural and morphological features were studied using X-ray diffraction, thermal analysis (TGA–DTA), Brunauer–Emmett–Teller, Raman spectroscopy and scanning electron microscopy (SEM–EDX). From commercial anatase powder, amorphous TiO 2 ME and O/W microemulsion ME238 (NaOH/TiO 2 molar ratio 238), biphasic nanoribbons were obtained: TiO 2 –(B) (88–92%) and anatase (8–12%). While from the O/W microemulsion ME30 (NaOH/TiO 2 molar ratio 30) only anatase phase was obtained. The material with higher TiO 2 –(B) phase content, showed an increase in its reversible capacity, thus the crystalline nature of the precursor as well as the textural properties contribute to the electrode performance. Materials synthesized from commercial anatase and amorphous TiO 2 ME exhibited similar charge retention (86–87%) despite the slight difference in reversible capacity, 210 and 180 mAh/g, respectively. It is noticed that TiO 2 –(B)–AME (prepared from amorphous TiO 2 ME) exhibited the lowest capacity loss, e.g. the highest reversibility.