Efficient removal of methylene blue by photocatalytic degradation with TiO 2 nanorod array thin films O ¨ zge Kerkez • I ˙ smail Boz Received: 12 February 2013 / Accepted: 26 July 2013 / Published online: 8 August 2013 Ó Akade ´miai Kiado ´, Budapest, Hungary 2013 Abstract TiO 2 nanorod array thin films were synthesized on fluorine doped tin oxide (FTO) glass substrate by the hydrothermal method. The prepared TiO 2 nanorod arrays were characterized by X-ray diffraction, scanning electron micros- copy and UV–Vis diffuse reflectance spectroscopy. The effect of different synthesis conditions was investigated on the growth and photocatalytic activity of the sam- ples. X-ray diffraction results show that the main phase of TiO 2 is rutile and nanorod growth significantly depends on the synthesis conditions. TiO 2 nanorod array thin films were used for the photocatalytic degradation of methylene blue in aqueous solution under UV irradiation (254 and 365 nm). The hydrothermal synthesis conditions of TiO 2 /FTO sample were determined for maximum photodegradation efficiency. Total degradation of 94 % was achieved under 254 nm and 69 % deg- radation was achieved under 365 nm with TiO 2 /FTO sample prepared with initial HCl:H 2 O = 1:1 ratio, 1.0 ml TiCl 4 at 180 °C for 2 h hydrothermal growth. The apparent reaction rate constant was calculated to be 0.0108 min -1 under 254 nm and 0.0044 min -1 under 365 nm. Keywords TiO 2 nanorod array  Hydrothermal method  Photocatalytic activity  Methylene blue degradation O ¨ . Kerkez (&) Chemical Engineering Department, Faculty of Engineering and Architecture, Beykent University, Ayazag ˘a Campus S ¸is ¸li, Istanbul, Turkey e-mail: okerkez@gmail.com I ˙ . Boz Chemical Engineering Department, Faculty of Engineering, I ˙ stanbul University, Istanbul, Turkey e-mail: ismailb@istanbul.edu.tr 123 Reac Kinet Mech Cat (2013) 110:543–557 DOI 10.1007/s11144-013-0616-8