Sonochemical Synthesis of Ti1−x−yFexPbyO2 (with x and y = 0, 0.01, 0.03, 0.07): Structural Analysis, Influence of Radiation Type on Photocatalytic Activity and Assessment of Antimicrobial Properties

Abstract

In this work, we report a method of obtaining and characterizing (Fe, Pb) co-doped titanium oxide nanoparticles to study the influence of Fe³⁺ and Pb²⁺ doping on the photocatalytic and antimicrobial properties of TiO₂. The presence of dopant elements can provide electronic changes by promoting a decrease in the band gap or creating intra-band gap states, thereby allowing greater absorption under visible light irradiation and potentially increasing the efficiency for developing photocatalytic and antimicrobial applications. Therefore, co-doped Ti_1−x−yFe_xPb_yO₂ (x and y = 0, 0.01, 0.03, 0.07 mol) powders were successfully obtained in a single step by the sonochemical method (SM). The structural, morphological and optical properties were evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), Field Emission Gun—Scanning Electron Microscopy (SEM-FEG) and UV–Visible spectroscopy (UV–Vis) techniques. The results showed the successful formation of the anatase phase of (Fe, Pb) co-doped TiO₂ by the SM with nanometric particles of irregular morphology. The photoluminescence exhibited low intensity for the co-doped samples, indicating a decrease in the recombination rate of the e−/h + electronic pair, which contributes to the photocatalytic efficiency. Optical measurements revealed a decrease in the band gap, providing possible energetic activation of these semiconductors by sunlight. The photocatalytic activity was estimated through the methylene blue dye (MB) degradation when exposed to UV light and Sunlight, and revealed that the type of radiation used to activate the photocatalysts influences the catalytic activity: T1F (Ti_0.99Fe_0.01O₂) and T1P (Ti_0.99Pb_0.01O₂) samples degraded the dye by 50% and 65% under UV light for 120 min, respectively, while the degradation under Solar irradiation was 98% and 99%, respectively. Antimicrobial properties were also investigated by agar diffusion method against E. coli (gram-negative) and S. aureus (gram-positive) bacteria and showed positive results of (Fe, Pb) co-doped TiO₂ samples compared to pure TiO₂. Accordingly, the results indicate that the co-doping of TiO₂ with Fe³⁺ and Pb²⁺ influences its potential application as photocatalysts and antimicrobial agents.

Graphical Abstract