Conjugated Polymer Modifying TiO2 Performance for Visible-Light Photodegradation of Organics

Cristina Giorgiana Coromelci; Elvira Turcu; Florica Doroftei; Mircea Nicolae Palamaru; Maria Ignat

doi:10.3390/polym15132805

Conjugated Polymer Modifying TiO₂ Performance for Visible-Light Photodegradation of Organics

Polymers (Basel). 2023 Jun 24;15(13):2805. doi: 10.3390/polym15132805.

Authors

Cristina Giorgiana Coromelci^{1

2}, Elvira Turcu³, Florica Doroftei³, Mircea Nicolae Palamaru¹, Maria Ignat^{1

3}

Affiliations

¹ Faculty of Chemistry, "Alexandru Ioan Cuza" University of Iaşi, 11 Carol I Blvd, 700506 Iaşi, Romania.
² Institute of Interdisciplinary Research, Department of Exact Sciences and Natural Sciences, "Alexandru Ioan Cuza" University, 11 Carol I Blvd, 700506 Iasi, Romania.
³ Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, 41A Grigore GhicaVoda Alley, 700487 Iasi, Romania.

Abstract

Up to now, the use of TiO₂ has been considered a promising advanced technology for organic pollutants removal from air or water, since it has high biological and chemical stability, high photoactivity, low toxicity, and low-cost production. However, there are issues to be addressed in enhancing TiO₂ performance, and one of the current key issues is redesigning UV-active photocatalysts and making them active in the visible region of the electromagnetic spectrum. This way, solar light absorption will be insured, and thus, a more efficient photocatalyst could be obtained. For this reason, conjugated polymers and their derivatives are considered to act as photosensitizers, being able to shift the TiO₂ activity from the UV to the visible region. Therefore, this study focuses on the synthesis of TiO₂/conjugated polymer systems, which was accomplished by the deposition of poly-3,4-ethylene-dioxy-thiophene (PEDOT [-C₆H₄O₂S-]_n), a low-band semiconductor with an excellent stability due to its extending π-conjugated electron system, on titania nanoarchitecture. First of all, a TiO₂ nanoarchitecture was synthesized by an ultrasound-assisted sol-gel method. Then, TiO₂/PEDOT systems were obtained and characterized by using different techniques such as X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, UV-Vis diffuse reflectance, and N₂ sorption measurements. The synthesized composites confirmed their mesoporosity and lower band gap values compared to bare titania, which clearly shows the ability to work as photocatalysts under visible-light activity. Further, we demonstrated that an organic pollutant, Congo Red dye, used as a model molecule could be photodegraded with the synthesized TiO₂/PEDOT systems, with efficiencies of up to 95% in the case of T_convPEDOT under UV light and up to 99% for T_convPEDOT under visible-light irradiation, accomplishing in this way a successful synthesis of visible-light-activated titania photocatalyst.

Keywords: TiO2; conjugated polymers; mesoporosity; organic pollutants; visible light.

Abstract

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