RGO–TiO2 pasteswere synthesized following the Grätzel method for
preparing TiO2 [32]. Before preparing the photoanode films, FTO conducting glass was immersed into a 40 mMTiCl4 aqueous solution at
70 °C for 30 min, and then a 0.6 × 0.6 cm2 film was coated on it by
doctor-blading technique. After drying at 125 °C, the RGO–TiO2 film
was heated up at 5 °C per minute to 500 °C and held for 3 h under the
nitrogen atmosphere to remove the organic component. The RGO–
TiO2 nanocomposite electrode was prepared after an extended posttreatment
using a TiCl4 aqueous solution followed by a sintering process
at 450 °C in air for 30min. Finally, the resulting electrodewas immersed
into an N719 ethanol solution for 24 h to form the sensitized
photoanode. For comparison, two kinds of electrodes are also prepared:
a pure TiO2 electrode and another made of 0.75 wt.% as-received GO
mixed with TiO2.