Controllable preparation of WO3 nanorod arrays by hydrothermal method

Abstract WO 3 nanorod arrays (WNRs) were synthesized on indium tin oxide conducting substrates by hydrothermal method. The effects of preparing conditions such as the precursor solutions concentration (H + and Na 2 WO 4 ), the additive NaCl, growth temperature and reaction time on the morphologies of WNRs have been systematically investigated by scanning electron microscopy, X-ray diffraction, Raman spectrum and ultraviolet visible absorption spectrum. It is shown that the pH value of the precursor solutions plays an important role in determining the morphology of as-prepared WNRs, which leads to different band gap energies. The orientation, density, and crystallinity of WNRs can be controlled by changing the amount of additive NaCl, Na 2 WO 4 concentration and reaction temperature, respectively. Moreover, the growth mechanism of the WNRs was also discussed.