Papers by Keyword: TTIP

Abstract: Titanium oxide, (TiO₂), can exist in three distinct crystallographic phases known as anatase, rutile, and brookite. Brookite, however, is the least known TiO₂ phases and usually exists as byproduct during synthesising rutile or anatase. Therefore, in this study, the influence of sol-gel pH and soaking time on surface morphology, phases and grain size of TiO₂ coating were investigated in an attempt to develop brookite thin film. Titanium (IV) isopropoxide (TTiP) is used as precursor for preparing TiO₂ sols. Prior to heating, TiO₂ layers were deposited on a glass slide by dipping it five times into TiO₂ sols. The TiO₂ layers were then heated at 450°C and soaked for 1 and 3 hours to form TiO₂ coating. Analysis on the phases and grain size were carried out using X-ray diffraction (XRD). The TiO₂ surface morphology was investigated using Scanning Electron Microscope (SEM). Results showed that brookite phase with grain size of 27.40 nm successfully deposited on glass slide from sols with pH¹². Conversely, the TiO₂ coatings deposited from sols of pH¹ and pH⁷ are amorphous. The effect of soaking time on phases and grain size is insignificant but enhances coatings uniformity as the soaking time increased. Thus, it can be concluded that sol-gel pH affect TiO₂ crystallinity and phases. Brookite film is develop only when the TiO₂ sols is in bases condition or at higher pH value.

Abstract: TiO₂ nanoparticles have been successfully synthesized using the sol-gel method with main materials of titanium tetraisopropoxide (TTIP) and HClO₄ solutions. Mass ratios (Rw) of aquadest and TTIP were 0.85, 2.00, and 3.50 which were going to be investigated in crystallization of TiO₂ phases. Pre-heating was performed on TiO₂ at 60°C for one day then it was annealed at 150°C for 3 hours. The DSSC structure was formed by using the synthesized-TiO₂ as semiconductor material and beta-carotene as dye sensitizer. The x-ray diffraction (XRD) spectrum indicated that TiO₂ peaks had anatase phases on crystal orientation of (101), (004), and (200) while TiO₂ of rutile phase only appeared on orientation of (211). The highest intensity for all Rw was dominated by (101) anatase phase. From XRD spectrum data of (101) peak, the Scherrer’s method predicted that crystal size of TiO₂ was 3.48 nm, 4.36 nm, and 4.47 nm for Rw of 0.85, 2.00, and 3.50, respectively. The Tauc’s method was applied on the UV-Vis data that predicted the bandgap energy (Eg) of TiO₂ for Rw of 2.00 (Eg=3.14 eV) was higher than Rw of 0.85 (Eg=3.02 eV) and 3.50 (Eg=3.04 eV). The I-V characteristic calculation of DSSC structures were obtained that the efficiency optimum is 0.01% for Rw of 2.00. It is considered that bandgap energy value correlated to stability of Ti-OH bonds that caused the exited-electrons are easily injected to conduction band of TiO₂. The performance of DSSC using the synthesized-TiO₂ which consists of anatase and rutile can be improved about ten times compared to that using the pure-TiO₂ rutile.

Abstract: Even though activated carbon fibers (ACF) have been attractive due to high specific surface area and uniform micropore structure, there are only a few reports about the photocatalyst immobilization on ACF or their photodegradation behavior for removal of organic pollutants. In this study, ACF were selected as adsorptive support for photocatalyst immobilization. As photocatalysts, TiO2 nanoparticles were synthesized by using a N2-diluted and oxygen-enriched co-flow hydrogen diffusion flame. The visible flame length of 150mm was obtained by direct photographs. Flame temperature was measured by rapid insertion measurement technique with a R-type (Pt/Pt-13%Rd) thermocouple which was in wire shape (127μm diameter). TiO2 particles were sampled by using a high temperature particle sampler and then were coated on ACF filters. The sampling was carried out at 70mm and 110mm above the burner. The structure of TiO2 particles was analyzed by XRD. TiO2 coated ACF filters were characterized by FESEM-EDX and BET analyses. TiO2 particles on ACF filters were found to be agglomerated particles and the size of primary particles was approximately 50nm. The structure of TiO2 particle was anatase-phase crystalline structure. The specific surface area of TiO2 coated ACF filter was enhanced to be 1700~1860m2/g, depending on the sampling location, and the pores were micropores, regardless of the sampling location.