Evaluating the sensitizing effect on the photocatalytic decoloration of dyes using anatase-TiO2

Yu Cheng Hsiao, Tsai Fang Wu, Yu Sheng Wang, Chi Chang Hu*, Ch-Hpin Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


This work tries to clarify the contribution of the dye-sensitizing effect on the photocatalytic decoloration of dyes dissolved in aqueous media using an anatase TiO2 (A-TiO2) photocatalyst. The photocurrent-voltage (J-V) curves of a typical dye-sensitized solar cell (DSSC) with the A-TiO2 photoanodes adsorbed with various dyes, including methylene blue (MB), orange G (OG), rhodamine B (RhB), metanil yellow (MY), acid black 24 (AB24), and N719, are employed to demonstrate the sensitizing characteristics of dyes on A-TiO2. Unlike RhB, the MB, OG, MY, and AB24 cannot work as the photo-sensitizer on A-TiO2 from the J-V curves of DSSCs, reasonably due to the unmatched band position between dyes and A-TiO2. In the photocatalytic decoloration test of these dyes on A-TiO2 in aqueous media, dye adsorption onto A-TiO2 becomes the key factors affecting the photocatalytic decoloration rate because the generation of oxidants species (e.g., O2-, OH• or photo-excited holes) occurs on the A-TiO2 surface. The contribution of dye-sensitizing on the photocatalytic decoloration of RhB is negligible since the dye-sensitizing/electron-injection/dye-regeneration cycle cannot be completed in the degradation media while adsorbed RhB molecules are unstable when few photo-generated electrons have been injected into the conduction band of A-TiO2, probably leading to the decomposition of RhB.

Original languageEnglish
Pages (from-to)250-257
Number of pages8
JournalApplied Catalysis B: Environmental
StatePublished - 27 Apr 2014


  • Dye decoloration
  • Dye-sensitizing effect
  • Photocatalysis
  • Photocurrent-voltage curve
  • Titanium dioxide


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