PREPARATION OF BLACK TITANIUM DIOXIDE (TIO2) USING HYDROGEN PLASMA IN A MICROWAVE-ASSISTED CHEMICAL VAPOR DEPOSITION (CVD) PLASMA REACTOR

• Main Author: Ilham
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/57351
• Institution: Institut Teknologi Bandung

Black TiO2 has been widely studied due to its wide range of light absorption from UV to visible region. The common preparation method of black TiO2 is still considered to be inefficient due to its time-consuming process. In this study, black TiO2 was prepared using hydrogen (H2) plasma in a microwave-assisted Chemical Vapor Deposition (CVD) plasma reactor to solve this drawback. This research studied the properties of H2 plasma produced in the microwave plasma reactor and the resulted black TiO2. The method consists of plasma reactor fabrication and H2 plasma modification of Aeroxide TiO2 P 25 nanoparticles. TiO2 nanoparticles were exposed to the H2 plasma for 1, 2, 3, and 4 h. The H2 plasma emission was studied using optical emission spectroscopy (OES). At the same time, the prepared black TiO2 was characterized using X-ray Diffraction (XRD), Raman, Fourier Transform Infrared (FTIR), and Ultraviolet-Visible Diffuse Reflectance (UV-Vis DRS) techniques. The optical emission spectra of the H2 plasma show typical emission of hydrogens, such as H?, H?, and H? lines, as well as the H2 Fulcher band. A significant color change in Aeroxide TiO2 P 25 nanoparticles was observed after 4 h of H2 plasma treatment resulted in black TiO2. XRD patterns indicate some typical diffraction peaks of TiO2 at a 2? of 25,26; 36.94; 37.81; 38.56; 48.01; 54.29; 55.05; 62.68; 68.87; 70.24; 75.10 ° that assigned to the anatase phase, while 27.34; 36.04; 41.24; 53.91; 56.57 ° to the rutile phase. The Raman spectra exhibit typical vibrational modes at 143.45; 197.25; 396.56; 517.15; 639.13 cm-1 that assigned to the anatase phase, while 449.76; 620.13 cm-1 to the rutile phase. The H2 plasma treatment leads to a blue shift in the Raman spectra of Aeroxide TiO2 P 25 nanoparticles. Both XRD and Raman results indicate a phase transformation from anatase to rutile during the H2 plasma treatment. FTIR spectra show some absorption bands attributed to TiO, (HO2)(H2), HO2, and TiH vibrations. The electronic transition type of black TiO2 can be described as an indirect forbidden transition with the bandgap energy of 2.80; 2.76; 2.48; 1.00; 0.89 eV for 0, 1, 2, 3, and 4 h of H2 plasma treatment, respectively.