Efficiency of sensitizing nano-titania with organic dyes and peroxo complexes

Organic dye-loaded reduced titanium dioxide as a broadband saturable absorber for ultrafast fiber lasers

As a rising star among metal oxide nanomaterials, titanium dioxide (TiO2) has been widely investigated and employed in optical applications because of its excellent optical properties. In this work, we demonstrate the efficient and broadband nonlinear photonic properties of methylene blue (MB)-loaded reduced TiO2 (TiO2-x-MB) and explore the performance of a TiO2-x-MB-microfiber photonic device in broadband ultrafast photonics. Within an erbium-doped fiber laser (EDFL) system, utilizing the TiO2-x-MB-microfiber photonic device as a saturable absorber (SA), steady mode-locked pulses together with chaotic pulses were successfully achieved at the wavelength of 1.55 μm. Furthermore, by incorporating the TiO2-x-MB SA into a thulium-doped fiber laser (TDFL) system, an ultrashort single pulse and multiple pulses were obtained at 2.0 μm. These results indicate that TiO2-x-MB is an excellent nanomaterial for use in mode-locked lasers, being an alternative candidate for ultrafast fiber lasers via exploiting the chemical and physical properties of oxide nanomaterials.

Titanium Dioxide Nanoparticles: Prospects and Applications in Medicine

Metallic and metal oxide nanoparticles (NPs), including titanium dioxide NPs, among polymeric NPs, liposomes, micelles, quantum dots, dendrimers, or fullerenes, are becoming more and more important due to their potential use in novel medical therapies. Titanium dioxide (titanium(IV) oxide, titania, TiO₂) is an inorganic compound that owes its recent rise in scientific interest to photoactivity. After the illumination in aqueous media with UV light, TiO₂ produces an array of reactive oxygen species (ROS). The capability to produce ROS and thus induce cell death has found application in the photodynamic therapy (PDT) for the treatment of a wide range of maladies, from psoriasis to cancer. Titanium dioxide NPs were studied as photosensitizing agents in the treatment of malignant tumors as well as in photodynamic inactivation of antibiotic-resistant bacteria. Both TiO₂ NPs themselves, as well as their composites and combinations with other molecules or biomolecules, can be successfully used as photosensitizers in PDT. Moreover, various organic compounds can be grafted on TiO₂ nanoparticles, leading to hybrid materials. These nanostructures can reveal increased light absorption, allowing their further use in targeted therapy in medicine. In order to improve efficient anticancer and antimicrobial therapies, many approaches utilizing titanium dioxide were tested. Results of selected studies presenting the scope of potential uses are discussed in this review.

Zinc Porphyrin-Functionalized Fullerenes for the Sensitization of Titania as a Visible-Light Active Photocatalyst: River Waters and Wastewaters Remediation

Zinc porphyrin-functionalized fullerene [C60] derivatives have been synthesized and used to prepare titania-based composites. The electrochemical properties and HOMO and LUMO levels of the photosensitizers were determined by electrochemical measurements. Raman and IR techniques were used to study chemical groups present on the titania surface. Absorption properties of the composites were measured in the solid state by diffuse reflectance UV-Vis spectra (DRS). The zeta potential and aggregate sizes were determined using dynamic light scattering (DLS) and electrophoretic light scattering (ELS) techniques. Surface areas were estimated based on Brunauer–Emmett–Teller (BET) isotherms. The photocatalytic activity of the photocatalysts was tested using two model pollutants, phenol and methylene blue. The composite with the highest photocatalytic potential (1/TiO₂) was used for river and wastewater remediation. The photodegradation intermediates were identified by LC-UV/Vis-MS/MS techniques.

Photocatalytic degradation of naproxen by a H2O2-modified titanate nanomaterial under visible light irradiation

A H₂O₂-modified titanate nanomaterial was synthesized to improve catalytic activity. The influencing factors, intermediate product transformation pathways and degradation mechanism of the photodegradation process of NPX by the HTNM were studied.

Introduction of peroxo groups into titania: preparation, characterization and properties of the new peroxo-containing phase

A new phase, where peroxo groups are incorporated into titania particles, along with anatase and hydrated η-TiO₂ with peroxo groups on the surface of titania nanoparticles were prepared.