Gatut Yudoyono

Effect of calcination temperature on the photocatalytic activity of TiO2 powders prepared by co-precipitation of TiCl3

The adsorption of basic dye methylene blue (MB) onto titanium dioxide (titania) powder that were prepared by coprecipitation method of TiCl3 and NH4OH as iniatial material with different calcination temperature was studied to examine the photocatalytic activity. Synthesis process carried out by the solution pH was adjusted to be 8. Effect of calcination temperature on the titania powder were characterized with Differential Scanning Calorimetry/Thermogravimetry (DSC/TG), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The result of TG and XRD showed that the NH4Cl decomposed between 235-372°C. The XRD result showed that the anatase TiO2 only contained a single phase when the calcination temperature of the precursor at 800°C, and over which it began to grow rutile phase. The influence of synthesis condition on the photocatalytic activity of TiO2 powder was determined by the photodegradation of MB dye under UV light.

Effect of Mixing Dyes and Solvent in Electrolyte Toward Characterization of Dye Sensitized Solar Cell Using Natural Dyes as The Sensitizer

Dye Sensitized Solar Cell (DSSC) using natural dyes (chlorophyll, curcumin from turmeric extract, and anthocyanin from mangosteen extract) have been successfully fabricated for determining the effect of variation natural dyes, mixing dyes and acetonitrile in electrolyte toward characterization of DSSC. DSSC consists of five parts namely ITO (Indium Tin Oxide) as a substrate; TiO2 as semiconductor materials; natural dyes as an electron donor; electrolyte as electron transfer; and carbon as a catalyst that can convert light energy into electric energy. Two types of gel electrolyte based on PEG that mixed with liquid electrolyte have utilized for analyzing the lifetime of DSSC. Type I used distilled water as a solvent whilst type II used acetonitrile as a solvent with addition of concentration of KI and iodine. The main purpose of study was to investigate influence of solvent in electrolyte, variation of natural dyes and mixing dyes toward an efficiency that resulted by DSSC. The result showed that electrolyte type II is generally better than type I with efficiency 0,0556 and 0,0456 %, respectively. An efficiency values which resulted from a variation of mixed three natural dyes showed the greatest efficiency compared to mixed two natural dyes and one dye, with an efficiency value can be achieved at 0,0194 % for chlorophyll; 0,111 % for turmeric; 0,0105 % for mangosteen; 0,0244% (mangosteen and chlorophyll); 0,0117 % (turmeric and mangosteen); 0,0158 % (turmeric and chlorophyll); and 0.0566 % (mixed three natural dyes).

Study on fabrication of TiO2 thin films by spin – coating and their optical properties

Study on fabrication of TiO2 thin films and their optical properties in UV-VIS spectrum has been conducted. TiO2 nanopowders were prepared by co-precipitation method with varying mixing duration for 5, 10 and 25 hours using TiCl3 as precursor. The as-synthesized TiO2 phase is anatase having crystalline size of 14.25 nm, 13.75 nm and 12.62, respectively for the corresponding mixing duration. Thin films of TiO2 were fabricated by spin coating method and then checked by XRD diffractometer and UV-Vis Spectrophotometer to examine their structure and band gap energy. The prepared films also contain anatase phase of TiO2 with respective band gap of 3.70 eV, 3.74 eV and 3.76 eV, depending on the powders and their treatment.Study on fabrication of TiO2 thin films and their optical properties in UV-VIS spectrum has been conducted. TiO2 nanopowders were prepared by co-precipitation method with varying mixing duration for 5, 10 and 25 hours using TiCl3 as precursor. The as-synthesized TiO2 phase is anatase having crystalline size of 14.25 nm, 13.75 nm and 12.62, respectively for the corresponding mixing duration. Thin films of TiO2 were fabricated by spin coating method and then checked by XRD diffractometer and UV-Vis Spectrophotometer to examine their structure and band gap energy. The prepared films also contain anatase phase of TiO2 with respective band gap of 3.70 eV, 3.74 eV and 3.76 eV, depending on the powders and their treatment.

Influence of pH on the formulation of TiO2 powder prepared by co-precipitation of TiCl3 and photocatalytic activity

Titanium dioxide (titania) nanoparticle were synthesized by coprecipitation process of titanium trichloride (TiCl3) in aqueous medium, with NH4OH as pH regulator. The pH solution was varied during the synthesis process between pH 3-8.4, and all samples were calcined temperature at 400°C for 3 hours. Characteristics and properties of the TiO2 powder were investigated using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM). XRD results show that the single-phase rutile formed when the pH is less than 5, anatase single phase formed began pH 8, and the pH of the solution between 5-8 formed mixed phase rutile-anatase-brookite, rutile-brookite or anatase-brookite. Methylene Blue (MB) photodegradation test were performed in order to evaluate photocatalytic activity. Nanoparticles TiO2 rutile, anatase phase, and mixed phase rutile-brookite, anatase-brookite used to test the photocatalytic activity by measuring the absorbance spectrum photodegradation using UV-Vis spectrometer. The test results showed th...