In the present study, the adhesion of TiO₂ nanotubes (TiO₂-NTs) to thicker substrates was improved by decorating them with metallic Ag nanoparticles (NPs) using the photo-reduction process. The obtained coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). X-ray diffraction (XRD) confirmed that all TiO₂-NTs crystallized in anatase after annealing at 400°C regardless of the anodization potential. The scanning electron microscopy (SEM) indicated that the TiO₂-NTs were uniformly distributed on the substrate with an ordered and vertically aligned morphology. It also revealed that the diameter of the TiO₂-NTs reached~100 nm. The decoration of TiO₂-NTs surface with silver nanoparticles was assessed by transmission electron microscopy (TEM). Moreover, a new scratch test mode called ‘wear mode’ was performed to evaluate the wear resistance of the coatings. Results obtained by the scratch tests proved that the decorated coating with Ag nanoparticles improved the interfacial adhesion. The friction coefficient decreased from 0.65 to 0.45 when pure TiO₂ was decorated with 10 min-Ag-NPs.The wear behavior was studied using a multi-pass scratch test. It was found that the wear volume reduced with the incorporation of Ag nanoparticles. The study of the damage mechanisms showed visco-elastic plastic deformation in the pure TiO₂ coating.

Air pollution remains a significant global health challenge, with contaminants like volatile organic compounds (VOCs) and pathogenic bacteria serving as a major contributor. Titanium dioxide nanotubes (TiO₂-NTs) have emerged as promising materials for air purification, owing to their high surface area, photocatalytic activity, and stability. In this context, this study investigates the controlled electrodeposition of platinum (Pt) nanoparticles onto TiO₂-NTs to enhance their photocatalytic properties for indoor air treatment applications. By optimizing the Pt nanoparticle size and distribution, we aim to improve the degradation of VOCs and the inactivation of airborne bacteria. A series of Pt/TiO₂-NTs catalysts with varying Pt nanoparticle sizes were synthesized via electrodeposition onto TiO₂-NTs fabricated via anodization of titanium foil. The structural and optical properties of the modified nanotubes were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). The resulting materials exhibited enhanced photocatalytic degradation of VOCs and effective inactivation of Escherichia coli (E. coli) under visible light irradiation, attributable to the synergistic effects of Pt and TiO₂-NTs. Notably, catalysts decorated with smaller Pt nanoparticles (10–22 nm) demonstrated the highest photocatalytic activity, emphasizing the critical influence of nanoparticle size on performance.

This study investigated the remediation of organic acid pollutants, specifically butyric acid (C₄H₈O) and valeric acid (C₅H₁₀O₂), as well as their binary mixtures in the vapor phase at various ratios. The remediation process involved the use of a continuous pilot-scale reactor. A TiO₂ catalyst was deposited on glass fiber tissue (GFT) and ultraviolet (UV) irradiation with an intensity of 20 W/m². The main objective of this study was to assess the effectiveness of the photocatalytic process by oxidizing and mineralizing a mixture of carboxylic acids in a rectangular reactor at pilot scale. This was achieved by calculating the removal efficiency and the selectivity of CO₂ (S_CO2). Each individual compound was treated separately, followed by the treatment of binary mixtures with molar fractions of 0.25, 0.5, and 0.75. The concentration of pollutants at the inlet varied between 50, 100, 150, and 200 mg/m³, while the flowrate ranged from 2 to 6 m³/h. The obtained results for the removal efficiency of butyric acid, the binary acid mixture (25% butyric acid + 75% valeric acid), and valeric acid were satisfactory, with percentages of 58%, 32%, and 41%, respectively. It is evident that the selectivity toward CO₂ is better for butyric acid compared to valeric acid and the binary carboxylic acid mixture, with values of 43.70%, 33.49%, and 21.96%, respectively, across all concentrations. A simulation model based on mass transfer and catalytic oxidation mechanisms was developed and successfully validated against the experimental data for each pollutant. Reusability tests conducted on the TiO₂ on GFT, both in its initial (clean) state and after 50 h of the photocatalytic treatment of butyric acid, showed a 15% decrease in photocatalytic efficiency.