Taguchi method for optimization of immobilized Dy2O3/graphite/TiO2/Ti nanocomposite preparation and application in visible light photoelectrocatalysis process

Abstract

In the first section of work, Taguchi's L9 orthogonal design was applied to investigate the effect of Dy2O3 and graphite masses, calcination temperature and voltage to prepare a new and optimized Dy2O3/graphite/TiO2/Ti electrode through the electrophoretic deposition process. The obtained optimum conditions with considering the visible light photoelectrocatalytic ability in decolorization and electrode stability were as follows: 7 mg Dy2O3, 50 mg graphite, calcination temperature of 400 °C and different voltage of 60 V. The results of SEM, EDX elemental mapping and XRD for the optimized Dy2O3/graphite/TiO2/Ti electrode indicated the uniform immobilization of Dy2O3, graphite and TiO2 particles on the Ti grid sheet. Moreover, the DRS approved the photo-absorption ability of the prepared electrode in the visible light range.In the second part, Taguchi's L16 orthogonal design was used to investigate the effect of pH, the number of Dy2O3/graphite/TiO2/Ti electrode(s), visible light power and applied bias potential on the photoelectrocatalytic ability of the prepared electrodes in the degradation of Maxilon Blue from well water. The obtained results showed that the maximum decolorization efficiency was achieved at the optimum conditions: pH of 10, two Dy2O3/graphite/TiO2/Ti electrodes, visible light power of 72 W and applied bias potential of 0.9 V. The decolorization efficiency of the photoelectrocatalysis process using the optimized electrodes was considerably higher than solo sorption, electrosorption and photolysis processes.