Enhanced photoabsorption properties of composites of Ti/TiO2 nanotubes decorated by Sb2S3 and improvement of degradation of hair dye

• TiO2/Sb2S3 electrodes are obtained by electrochemical and chemical deposition.
• TiO2/Sb2S3 composite present lower band gap energy (1.68 eV).
• TiO2/Sb2S3 electrode offer strong photoabsorption in the UV/visible light regions.
• TiO2/Sb2S3 showed superior photoelectrocatalytic activity than the bare TiO2 NTs.

The present work illustrates the great potentiality of Ti/TiO2/Sb2S3 composite electrode prepared by electrochemical anodization of Ti foil in aqueous electrolyte (1 mol L−1 NaH2PO4 + 0.3 wt.% HF followed by chemical bath deposition of Sb2S3) in environmental electrochemistry. The electrodes are characterized by deposits of particles of 500 nm of diameter formed on the top of TiO2 nanotubes of 900 nm of length, 110 nm of diameter and 13 nm of wall thickness. The band gap obtained for Ti/TiO2/Sb2S3 composite electrode was 1.68 eV, contributing to strong photoabsorption properties of the material in the visible light region (λ < 740 nm). The photocurrent on this material is remarkably improved in relation to that obtained on comparable nanotubes TiO2 films. The electrodes promote complete degradation of the investigated hair dyeing commercialized as Arianor Tyrian Purple® after 120 min of photoelectrocatalytic oxidation under potential of 1.2 V and commercial light irradiating under UV/Visible light. Finally, the degradation products generated by photoelectrocatalysis were analyzed by HPLC–MS/MS.

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