Now showing 1 - 6 of 6
  • Publication
    Surface Modification of GO/TiO2 Thin Film by Sodium Dodecyl Sulphate for Photocatalytic Applications
    Photocatalyst material titanium dioxide (TiO2) and graphene oxide (GO) were used to improve the self-cleaning properties of thin films. The sol–gel spin-coating method was successfully used to synthesize GO/TiO2 thin films. Surface modification was applied to optimize the self-cleaning capabilities by adding several concentrations of sodium dodecyl sulfate (SDS) (0.1 w/v%, 0.2 w/v%, 0.3 w/v%, 0.4 w/v%, and 0.5 w/v%) to the parent solution. The synthesized thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, UV-visible spectroscopy, water contact angle analysis, and photocatalytic analysis. The AFM and SEM images revealed that as the SDS amount increased, the particles became less agglomerated, and the roughness of the surface reduced from 2.54 × 102 nm to 0.83 × 102 nm. The wettability analysis showed that when SDS increased to 0.4 w/v%, the water contact angle dropped to 15.30°, implying that the thin film exhibits hydrophilic qualities. A decrease in the GO/TiO2 band gap was obtained linearly with the increase in SDS addition from 3.17 eV to 2.75 eV. Finally, the improvement of the surface coating and reduction of the band gap enhanced the photocatalytic activity, which degraded 78.97% of methylene blue, which was obtained by 0.4SDS.
      2
  • Publication
    The effect of GO/TiO2 thin film during photodegradation of methylene blue dye
    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.
      4  1
  • Publication
    The effect of polyethylene glycol addition on wettability and optical properties of GO/TiO2 thin film
    Modification has been made to TiO2 thin film to improve the wettability and the absorption of light. The sol-gel spin coating method was successfully used to synthesize GO/TiO2 thin films using a titanium (IV) isopropoxide (TTIP) as a precursor. Different amounts of polyethylene glycol (PEG) (20 to 100 mg) were added into the parent sol solution to improve the optical properties and wettability of the GO/TiO2 thin film. The effect of different amounts of PEG was characterized using X-ray diffraction (XRD) for the phase composition, scanning electron microscopy (SEM) for microstructure observation, atomic force microscopy (AFM) for the surface topography, ultraviolet–visible spectrophotometry (UV-VIS) for the optical properties and wettability of the thin films by measuring the water contact angle. The XRD analysis showed the amorphous phase. The SEM and AFM images revealed that the particles were less agglomerated and surface roughness increases from 1.21 × 102 to 2.63 × 102 nm when the amount of PEG increased. The wettability analysis results show that the water contact angle of the thin film decreased to 27.52° with the increase of PEG to 80 mg which indicated that the thin film has hydrophilic properties. The optical properties also improved significantly, where the light absorbance wavelength became wider and the band gap was reduced from 3.31 to 2.82 eV with the presence of PEG.
      1  2
  • Publication
    Synthesis of Zn/TiO2 Thin Films for Self-Cleaning Applications
    ( 2022-07-01) ;
    Abidin A.S.Z.
    ;
    Azani A.
    ;
    ; ; ; ;
    Sandu A.V.
    ;
    Vizureanu P.
    ;
    Kaczmarek L.
    ;
    Garus S.
    ;
    Garus J.
    Titanium dioxide (TiO2) thin film has been widely used in semiconductor applications. The surface modification on TiO2 has been done by adding zinc (Zn) in order to improve surface wettability and enhance the photocatalysis efficiency for solar cell applications. Self-cleaning technology is very important to sustain the efficiency of the solar cell and reduce the cost of the maintenance of the solar cell. In this work, the sol–gel method was used due to the economic factor and its best efficiency. The sol–gel method is a wet chemical technique involving several steps, such as hydrolysis and polycondensation, gelation, aging, drying, densification, and crystallization. The X-Ray diffraction pattern shows that anatase and rutile phases were detected at 2θ = 36.3864◦. It was clearly seen at 4% Zn-doped TiO2 annealed at 400◦C that due to the increment of Zn concentration, the phase transformed from the anatase phase to the rutile phase at high temperature. The scanning electron microscope micrograph shows that Zn concentration affects grain size. The water contact angle produced when 4% Zn-doped TiO2 was annealed at 300◦C, was 18◦ — higher than in the sample of 4% Zn-doped TiO2 annealed at 400◦C. These results clearly showed that the dopant concentration and the annealing temperature influence the properties of TiO2 for a self-cleaning application.
      2
  • Publication
    Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film
    In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.
      1
  • Publication
    The Effect of GO/TiO2 Thin Film During Photodegradation of Methylene Blue Dye
    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.
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