Enhanced Sonocatalytic Degradation of Organic Pollutants Using Noble-Metal-Doped Electrospun TiO2 Nanofibers

Abstract

In this study, the sonocatalytic oxidation performance of electrospun TiO2 nanofibers modified with noble metals (Pt, Pd, Ag, Ce, Cu) was systematically investigated for the degradation of Rhodamine B (RhB) as a model organic pollutant. TiO2 nanofibers were synthesized via the electrospinning method and calcined at 550 °C to obtain stable anatase-phase structures. Metal incorporation was performed through wet impregnation followed by thermal treatment, resulting in homogeneously dispersed metal nanoparticles anchored on the TiO2 surface. Characterization analyses (SEM, XRD, FTIR, BET) confirmed uniform fibrous morphology, preservation of the anatase phase, and increased surface area upon metal loading. Sonocatalytic degradation experiments were conducted under varying pH (3–10) and oxidant (H₂O₂) concentrations. Among the investigated catalysts, the sonocatalytic activity followed the order Pt–TiO₂ > Ce–TiO₂ > Cu–TiO₂ ≈ Pd–TiO₂ > TiO₂ > Ag–TiO₂, with Pt–TiO₂ exhibiting the highest RhB degradation efficiency. Among the tested catalysts, Pt–TiO2 nanofibers exhibited the highest degradation efficiency (~95%), followed by Ce–TiO2 (~70%), while Pd–TiO2 and Cu–TiO2 showed moderate activity (45–55%). The Ag–TiO2 sample displayed the lowest performance (~40%) due to possible nanoparticle aggregation and reduced active surface area. Kinetic analysis revealed that the degradation process predominantly followed pseudo-first-order kinetics, with apparent rate constants (k) of 0.0020, 0.0146, 0.0033, 0.0005, 0.0011, and 0.0034 min⁻¹ for TiO₂, Pt–TiO₂, Pd–TiO₂, Ag–TiO₂, Ce–TiO₂, and Cu–TiO₂, respectively. The optimal degradation occurred at neutral pH, whereas the addition of 0.001 M H₂O₂ lowered efficiency through radical scavenging effects. These results demonstrate that noble-metal-enriched TiO2 nanofibers synthesized via electrospinning possess high activity, stability, and recyclability under ultrasonic irradiation, offering great potential for sustainable wastewater treatment and the advancement of green sonochemical oxidation technologies.

Keywords

• Sonocatalytic oxidation
• TiO2 nanofiber
• Precious metals
• Rhodamine B
• Ultrasound

Supporting Institution

Office of Scientific Research Projects Coordination at Konya Technical University, Grant number: 232022042.

Project Number

Office of Scientific Research Projects Coordination at Konya Technical University, Grant number: 232022042.

Ethical Statement

Ethics committee approval was not required for this study because there was no study on animals or humans.

Thanks

This work was supported by the Office of Scientific Research Projects Coordination at Konya Technical University, Grant number: 232022042.

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