This research reports a simple, innovative, and low-cost doping method of TiO₂ nanoparticles presenting the effects of calcination and the weight ratio of TiO₂:FeCl₃ (1:0.33–1:4.5). The photocatalytic activity of the nanomaterials was investigated by decolorizing Rhodamine B (RhB) dye in an aqueous solution. The main results showed that there is anatase-to-rutile transformation after the calcination process. The Fe-doped process modified the TiO₂ spectrum and showed a connection in the Ti–O–Fe vibration. The particle size is within the nanometer range, between 20–51 nm, except for calcined TiO₂. The inclusion of Fe in TiO₂ decreased the band gap energy from 3.16 (reference) up to 2.06 eV (1:3). Additionally, after the calcination, there was a decrease in this value from 3.03 eV (reference) up to 1.95 eV (1:1.6). The TiO₂, with a ratio of (1:1.6), showed the highest activity in the photocatalytic degradation of RhB with an efficiency of 93.8% after 3 h of irradiation.

Aging by oxidation of asphalt roadway material promotes changes in its physical, chemical, and rheological properties, affecting its hardening and accelerating the degradation of its corresponding asphalt mixture. Titanium dioxide (TiO₂) has been applied in engineering investigations to promote anti-aging and photocatalytic properties. In this study, a commercial binder was modified with nano-TiO₂ (using contents of 0.1, 0.25, 0.5, 1, 2, 3, and 6%). It was evaluated by physicochemical and rheological tests (penetration, softening point, mass loss, dynamic viscosity, rheology, and Fourier transform infrared spectroscopy—FTIR) before and after aging by rolling thin-film oven test (RTFOT) and pressure aging vessel (PAV). The results indicated that incorporating nano-TiO₂ mitigates binder aging, pointing out 0.25% as an optimum modification content for the investigated asphalt binder.

The sustainable development of our societies demands strong efforts on scientific and technological research while informing and educating students and the general population. Air pollution and road safety hazards constitute two main public health problems that are insufficiently addressed pedagogically. With this work, we aim to contribute to tackeling the problem by presenting the results of scientific research on the development of photocatalytic, superhydrophobic, and self-cleaning recycled asphalt mixtures to achieve an eco-social friendly and smart material able to mitigate socioenvironmental impacts. The functionalization of asphalt is implemented by spraying particles’ solutions over a conventional AC 10, then evaluated by dye degradation and wettability. Firstly, different particles’ solutions (with nano-TiO₂ and/or micro-PTFE under water, ethyl alcohol, and dimethyl ketone) were sprayed to select the best solution (BS), which was composed of TiO₂-PTFE (4 g/L each) in ethyl alcohol. Two successive spraying coatings (diluted epoxy resin and BS) were performed over conventional and recycled AC 10 (with reclaimed asphalt pavement and steel slags). Their efficiency decreases with the highest resin amounts. The best results were obtained with 0.25 g resin and BS. For the lowest resin amount, all mixtures achieved superhydrophobicity and performed similarly regarding wettability.

To achieve high photocatalytic activity, TiO₂ nanoparticles nanoparticles require an excitation source in ultraviolet radiation. Incorporating chemical elements into the TiO₂ lattice can tune its band gap, resulting in an edge-shifted red absorption to reduce energies, improving photocatalytic performance in the visible region of the electromagnetic spectrum. In this research, TiO₂ semiconductor nanoparticles were subjected to a doping process using iron chloride (FeCl₃) powder to activate photocatalysis under visible light and consequently improve pollutant capture. To study the effectiveness of the doping process, the main ratios (1:1), (1:1.622) and (1:3) of TiO₂:FeCl₃ were evaluated using Diffuse Reflectance Spectroscopy (DRS), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The main results of this research show that doping TiO₂ with FeCl₃ shifted the absorption edge to longer wavelength values, changing the optical properties of the material and decreasing the band gap (E_g) of TiO₂ compared to the undoped TiO₂ (reference). There are no relevant differences between the XRD pattern of the samples with TiO₂-FeCl₃ and TiO₂ nanoparticles (reference). The fraction of the anatase phase in doped TiO₂ nanoparticles has the same magnitude as the reference TiO₂. Regarding FTIR, the Fe-doping process alters the TiO₂ reference spectrum, increasing the intensity of hydroxyl bonds and peaks particularly, indicating the Ti-O-Fe bond vibration.

This study investigates the effect of iron-modified nano-TiO₂, using the co-precipitation method with different concentrations of FeCl₃ (0.1, 1, and 10%), to improve its photocatalytic properties for outdoor applications. To this end, modified and unmodified nano-TiO₂ were characterized using different techniques. The optical properties were characterized by diffuse reflectance spectroscopy (DRS) followed by band gap calculation. X-ray diffraction (XRD) was used to analyze the crystalline structure. Chemical and morphological characterization were carried out using energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The photocatalytic activity was investigated by decolorizing Rhodamine B aqueous solutions under similar sunlight irradiation. The results indicate that the modification improved light absorption in the UV range for all iron concentrations; however, only the concentration of TiO₂: FeCl₃ (10%) shifted the absorption to the visible region. Also, including Fe³⁺ in TiO₂ decreased the band gap energy from 3.14 to up to 2.80 eV. There were variations in crystallite size from 21.13 to up to 40.07 nm. The nano-TiO₂ morphology analysis showed that it did not change after iron modification. EDS showed an FeCl₃ peak only at higher concentrations (10%). In addition, the 0.1% Fe-modified TiO₂ exhibited the highest activity in the photocatalytic process, with an efficiency of 95.23% after 3 h of irradiation.