Enhancement of the photocatalytic response of Cu-doped TiO2 nanotubes induced by the addition of strontium

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2022-06, Vol.428, p.113858, Article 113858
• Main Authors: Alrashedi, W., Kochkar, H., Berhault, G., Younas, M., Ben Ali, A., Alomair, N.A., Hamdi, R., Abubshait, S.A., Alagha, O., Gondal, M.F., Haroun, M., Tratrat, C.
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Copper; Photodegradation; Strontium; TiO2 nanotube
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2022.113858

[Display omitted] •Design of Strontium doped anisotropic Cu/ TiO2 nanomaterials.•Sr-O-Ti entities enhances photogenerated charges storage at the surface of the TiO2 nanotube semiconductor.•Optimized ferroelectric properties in presence of adjacent SrTiO3 surface domains.•Photogenerated charges can remain 75% longer at the semiconductor interface. The influence of adding strontium to Cu-doped TiO2 nanotubes on the photocatalytic performance of the resulting materials was herein studied considering changes in structural, textural, optical and morphological properties. Addition of strontium was performed in a 0.2–1.0 wt% range while an optimized fixed Cu loading of 0.5 wt% was used. TiO2 nanotubes were obtained using alkaline hydrothermal treatment of P25 followed by a calcination treatment at 400 °C. The resulting TiNT material was then impregnated with copper using an incipient wetness impregnation followed by a new calcination at 400 °C (0.5Cu-TiNT). Strontium was then added under similar impregnation-calcination conditions. The effect of adding various amounts onto 0.5Cu-TiNT was therefore deeply characterized using X-ray diffraction, N2 adsorption–desorption measurements, scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman, UV–vis diffuse reflectance, X-ray photoelectron, and photoluminescence spectroscopies as well as determining dielectric properties. Results clearly emphasize that up to a Sr loading of 0.8 wt%, the addition of Sr results in in situ formation of Sr-O-Ti entities on the surface of 0.5Cu-TiNT. Above this threshold loading, excess Sr loading leads to the formation of segregated SrO species. Finally, a direct correlation was observed here between the optimized formation of surface Sr-O-Ti entities and an enhanced photocatalytic response due to improved stabilization of photogenerated charges on 0.5Cu-TiNT resulting from the ferroelectric interference of neighboring SrTiO3 entities.