Volume 8 Issue 3 ( September 2021 )

Titanium (IV) isopropoxide (TTIP) was used to synthesize GO/TiO₂ thin films using a sol-gel spin-coating method onto a glass substrate, undergoing an heat tretment at 350 °C. Several amounts of graphene oxide (GO) (0-20mg) were weighed into a sol solution of TiO₂ to produce GO/TiO₂ thin films. The thin film samples were characterized by X-ray diffraction (XRD) to analyze the samples’ phase and by scanning electron microscopy (SEM) to analyze the samples’ microstructure. Physical testing such as water contact angle (WCA) was analyzed using an optical microscope with J-Image software. In contrast, the optical band gap and photodegradation of methylene blue under sunlight irradiation of the thin film was analyzed using UV-VIS spectrophotometry. GO₅ thin film sample showed low-intensity anatase phase formation, where the microstructure revealed a larger surface area with the addition of GO. WCA reveals that GO/TiO₂ thin film exhibits super hydrophilic properties where the angle decreases from 37.83° to 4.11°. The optical result shows that GO has improved the absorption edges by expanding into visible regions. Moreover, due to the existence of GO 3.30 eV band gap energy of TiO₂ decreases from to 3.18 eV obtained by GO₅. The improved adsorption edge allows Ti³⁺, O₂ and interstitial states to be formed in low valence states with energy underneath than in the TiO₂ band gap. Therefore, the photodegradation of methylene blue (MB) dye increases from 48 % to 59 % in the GO/TiO₂ thin film.

Keywords: Photodegradation, methylene blue, thin-film, water contact angle, graphene oxide