The photocatalysis of TiO2 nanotubes (Ti/TNT) and Ni-deposited TiO2 nanotubes (Ti/TNT-Ni) for methyl orange degradation was investigated. Methyl orange was selected as the model pollutant, and its photocatalytic degradation was determined in 1 mol/L KOH solution. Ti/TNT was produced by anodizing method, and the electrodeposition of nickel on TNT was performed galvanostatically. The characterization of electrodes was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The electrochemical behavior of the electrodes was determined by cyclic voltammetry and electrochemical impedance spectroscopy. The irradiation was applied by visible light source (lambda = 635 nm) for 48 h. UV/vis spectroscopy was used for determination of the concentration of methyl orange. Furthermore, after 48-h irradiation, the solutions were analyzed by Fourier transform infrared spectroscopy. Results showed that the concentration of methyl orange decreased from 100 ppm (10(-6)) to 16 ppm, after 48-h irradiation with the photocatalysis of Ti/TNT-Ni.