The degradation of azo dye Orange G

The degradation of azo dye Orange G (OG) on TiO2/Ti electrode was studied using a photoelectrocatalytic
system. TiO2/Ti electrode was prepared by electrophoretic deposition (EPD) process. Results of surface
analyses, namely, X-ray diffraction (XRD), SEM, X-ray photoelectron spectroscopy (XPS), and linear sweep
voltammetry (LSV), revealed that the optimal EPD condition was a deposition potential of 180 V for 1 min
and annealed at 350
C. The TiO2/Ti electrode was used as photoanode and a graphite cathode for the
degradation of OG. The coupling effect of photocatalytic and electrochemical oxidation processes was
evaluated in terms of the decolorization of OG. The degradation of OG increased in the following increasing
order: photocatalysis < electrochemical oxidation < photoelectrochemical degradation. A decolorization
of 54.3% was achieved at an applied current density of 75 lA cm
2. The degradation of Orange
G follows the first-order kinetics in those three treatment processes, which suggests the participation
of OH radicals in the decolorization reaction.