Organic dye-sensitized TiO 2 as a versatile photocatalyst for solar hydrogen and environmental remediation

Sung Kyu Choi, Hyun Sik Yang, Jae Hong Kim, Hyunwoong Park

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113 Scopus citations

Abstract

This study explores the applicability of organic dye-sensitized TiO 2 particles in the production of molecular hydrogen and remediation of environmental pollutants (4-chlorophenol and Cr(VI)) under visible light (λ>420nm). In order to examine the effect of number of anchoring groups, Ru-free organic dyes of donor-π-acceptor configuration are prepared with different numbers (n) of carboxylate anchoring groups (n=1, 2, and 3; referred to as D1, D2, and D3, respectively). All the three dyes are found to be effective at producing H 2 in the presence of electron donors (triethanolamine (TEOA) and ethylenediaminetetra-acetic acid (EDTA)) with the following orders: D3-D2>D1 (TEOA) and D3>D2-D1 (EDTA). FTIR studies reveal that D1 and D3 are anchored to the TiO 2 surface primarily via bidentate modes with a single carboxylate and two carboxylates, respectively. D2, in contrast, is anchored with one or two carboxylates, depending on the competing electron donors. The number of carboxylates is less important in the sensitized remediation of pollutants likely due to different photochemical conditions (oxic vs. anoxic) and various reaction pathways. A detailed systematic study is performed, including the UV-vis absorption characterization of free dyes and dye/TiO 2 samples, the photoelectrochemical behaviors of dye/TiO 2 electrodes, and the effects of dye concentrations, solution pH, and TiO 2 kind (Degussa P25 vs. Hombikat UV-100).

Original languageEnglish
Pages (from-to)206-213
Number of pages8
JournalApplied Catalysis B: Environmental
Volume121-122
DOIs
StatePublished - 13 Jun 2012

Keywords

  • Artificial photosynthesis
  • Cr reduction
  • Dye structure
  • Electron donors
  • Water splitting

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