Accelerated Photo‐Induced Degradation of Benzidine‐p‐Aminothiophenolate Immobilized at Light‐Enhancing TiO2 Nanotube Electrodes

• Published in: Chemistry : a European journal 2019-12, Vol.25 (70), p.16048-16053
• Main Authors: Querebillo, Christine Joy, Öner, Ibrahim Halil, Hildebrandt, Peter, Ly, Khoa Hoang, Weidinger, Inez M.
• Format: Article
• Language: English
• Subjects: azo compounds; Azo dyes; Chemistry; Decay rate; Degradation; Dyes; Electrodes; Electromagnetic fields; Nanotubes; Photodegradation; photonic activity; Photonics; Raman spectroscopy; Rate constants; resonance Raman spectroscopy; Time dependence; Titanium dioxide
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201902963

Herein, the enhanced visible‐light‐induced degradation of the azo‐dye benzidine‐p‐aminothiophenolate immobilized on TiO2 nanotube electrodes is reported. Exploiting the reported photonic properties of the TiO2 support and the strong electronic absorption of the dye allowed for employing surface‐enhanced resonance Raman spectroscopy at 413 nm to simultaneously trigger the photoreaction and follow the time‐dependent decay process. Degradation rate constants of up to 25 s−1 were observed, which stand among the highest reported values for laser‐induced degradation of immobilized dyes on photonically active supports. Contrast experiments with two differently light‐enhancing TiO2 nanotube electrodes establish the direct correlation of the material's optical response, that is, electromagnetic field enhancement, on the interfacial photocatalytic reaction. Enhanced degradation rates of benzidine‐p‐aminothiophenolate on TiO2 nanotube electrodes were derived. The photonic properties of the TiO2 support and the strong electronic absorption of the dye allowed for employing surface‐enhanced resonance Raman spectroscopy to simultaneously trigger the photoreaction and follow the time‐dependent decay process.