Photoelectrocatalytic Degradation of Triazine-Containing Azo Dyes at γ-Bi_2M_0O_6 Film Electrode under Visible Light Irradiation (γ ＞ 420 Nm)

摘要

Triazine-containing azo dyes, anionic reactive brilliant red K-2G, reactive brilliant Red X-3B, and reactive yellow KD-3G were degraded in the electrooxidation, photocatalysis and combined electrooxidation and phtocatalysis process at the γ-Bi_2M_0O_6 film electrode under visible light irradiation. Furthermore, in the combined process, synergetic degradation of the dyes was observed by the analysis of degradation kinetics and total organic carbon variation. The synergetic mechanism was studied using X-ray photo-electron spectra and electrochemical impedance spectra as well as analysis of variation of current vs time in various processes. It is suggested that application of bias potential with a lower value than the redox potential of the targeted dyes efficiently increases the photocatalysis rate of the dyes by prohibiting recombination of electrons and holes.