Self-organized TiO2 nanotube arrays in the photocatalytic degradation of methylene blue under UV light irradiation

• Published in: Journal of the Korean Physical Society Vol. 66; no. 7; pp. 1135 - 1139
• Main Authors: Chung, Eun Hyuk, Baek, Seong Rim, Yu, Seong Mi, Kim, Jong Pil, Hong, Tae Eun, Kim, Hyun Gyu, Bae, Jong-Seong, Jeong, Euh Duck, Khan, F. Nawaz, Jung, Ok-sang
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.04.2015; 한국물리학회
• Subjects: Mathematical and Computational Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Theoretical; 물리학; nanotube arrays; Electrochemical anodic oxidation; TiO; Photocatalytic behaviors; Methylene blue
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.66.1135

Nanostructured titanium dioxide (NTiO 2 ) is known to possess efficient photocatalytic activity and to have diverse applications in many fields due to its chemical stability, high surface area/volume ratio, high transmittance, and high refractive index in the visible and the near-ultraviolet regions. These facts prompted us to develop TiO 2 nanotube (TiO 2 NT) arrays through electrochemical anodic oxidation involving different electrolytes comprised of phosphoric acid — hydrofluoric acid aqueous systems by varying the voltage and the time. The annealing temperature of the nanotubes, TiO 2 NTs, were varied to modify the surface morphology and were characterized by using X-ray diffraction and scanning electron microscopy. Scanning electron microscopy and X-ray diffraction results showed that the samples had uniform morphologies and good crystalline structures of the anatase phase at lower annealing temperatures and of the rutile phase at higher annealing temperatures. A secondary-ion mass-spectrometry analysis was used to investigate the surface atoms and to conduct a depth profile analysis of the TiO 2 NTs. The efficiency of the photocatalytic activity of the TiO 2 NT arrays in degrading methylene blue (MB) was investigated under UV-Vis light irradiation. The maximum photocatalytic activity was achieved for the samples with lower annealing temperatures due to their being in the anatase phase and having a higher surface area and a smaller crystal size, which play important roles in the degradation of organic pollutants.