This work focuses on modeling and optimizing the deposition of a TiO2 film on ITO glass using the spin-coating method and experimental design. The parameters studied include the concentration of the solution, speed and duration of rotation, drying temperatures and time, and calcination temperature and time. Results show that optimal conditions are achieved at 457 g/l concentration, 1020 rpm speed, 43 s duration of rotation, 100 °C drying temperature for 30 s, and 500 °C calcination temperature for 2 h. XRD, FTIR, EDX, and SEM analyses of the TiO2/ITO film indicate crystallization in the anatase phase with a 29.3 nm crystal size and around 80% deposition quality, with good surface adhesion and a thickness of approximately 30 nm. The photocatalytic activity of the thin film for the decomposition of methylene blue (MB) in water was also studied. Results showed a 70% degradation of MB after 4.5 h, which was confirmed by absorption spectra and discoloration of MB. Additionally, the degradation reaction of MB by TiO2 followed the pseudo-first-order, with good agreement between the kinetic study and a high degradation rate constant (k 1deg = 0.2919 (h−1)), indicating a rapid process. Finally, a photodegradation mechanism of MB was reported.

In this work, the electronic structure, magnetic and optical properties of the anatase phase of titanium dioxide (TiO₂) were etudiée by the Density Functional Theory (DFT) method, using the GGA+U method. As a result, the magnetic electronic properties show that anatase is a non-magnetic semiconductor with an indirect gap of 3.202. Optical properties such as dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient and conductivity were found to be 8.21, 2.91, 1.98, 0.532, 517000 cm^-1 and 8.9 fs^-1 respectively. These results are in agreement with the available experimental results.

In this work, we will present a new protocol to identify solid matter quickly, and at low cost, by physico-chemical analysis methods. The fast and less expensive methods for identification that we investigate, using principal component analysis (ACP), are hydrogen potential (pH), electrical conductivity, density and solubility.

In this work, first-principles Density Functional Theory (DFT) calculations within the GGA + U framework were performed to investigate substitutional nitrogen-doped anatase TiO ₂ at nitrogen concentrations of 3.125, 6.25, and 12.5 at.%. Unlike previous studies, which mainly focused on a single doping concentration or a limited set of physical properties, this work provides a comprehensive investigation of the influence of nitrogen concentration on the structural, electronic, magnetic, and optical properties of anatase TiO ₂ within a unified computational framework. The optimized structures confirm that the anatase phase remains structurally stable after nitrogen substitution, exhibiting only slight local distortions around the Ti–N bonds. Electronic structure calculations reveal that increasing the nitrogen concentration progressively reduces the band gap from 3.20 eV for pristine TiO ₂ to 2.91, 2.819, and 2.625 eV for 3.125, 6.25, and 12.5 at.% N, respectively. This band-gap narrowing originates from the hybridization between N-2p and O-2p states, while the conduction band remains predominantly composed of Ti-3d states. The reduction of the band gap extends the optical absorption edge toward the visible region, enabling more efficient utilization of solar radiation and consequently enhancing the photocatalytic performance of TiO ₂ under visible-light irradiation. Spin-polarized calculations further demonstrate that nitrogen substitution preserves the non-magnetic nature of anatase TiO ₂ . Optical analyses reveal a pronounced red shift of the absorption edge, together with enhanced visible-light absorption and improved dielectric and optical responses as the nitrogen concentration increases. Among the investigated systems, the 12.5 at.% N-doped TiO ₂ exhibits the strongest visible-light response owing to its narrowest band gap and highest absorption intensity in the visible range, making it the most promising candidate for photocatalytic applications. These findings provide a comprehensive theoretical understanding of the concentration-dependent effects of nitrogen doping on anatase TiO ₂ and offer valuable guidelines for the rational design of high-performance visible-light-driven TiO ₂ photocatalysts and advanced optoelectronic materials.