Figure 2

SEM images of (a) Ti mesh before the hydrothermal reaction, (b) after the first-step reaction taking 12 h (H2Ti2O5·H2O on Ti mesh), and (c) after the second-step reaction (TiO2/Ti-M). (d) A TEM image of a TiO2 fiber deposited on the TiO2/Ti-M after the two-step hydrothermal reaction (first step: 12 h, second step: 24 h). A magnified fringe pattern is shown in the inset.