TiO2 nanopowders obtained using different methods with the mean size of 5, 15, and 30 nm have been investigated by Raman spectroscopy in wide spectral range. Nano-size of TiO2 crystals lead to a shift and broadening of the first-order Raman lines through a relaxation of the q = 0 selection rule and effects on to the position, width and asymmetry of a Raman bands. The details of the evolution of the 142.9 cm-1 Raman line shape on the size and distributions of the nanopowders are presented and discussed in frame of confined phonons model. Analysis of Raman spectra shows that structural characteristics of nanopowders may be different even size of the nanopowders is the same. Structural features of the material depend on preparation methods/conditions and can be extracted from Raman spectra of the material.

The biocompatibility of an implant material depends on the bulk physical properties in addition to the surface properties. In biomedical engineering and industry Ti and Ti-alloys are very popular biological implant material for their bulk physical properties and strength to weight ratio resembling those of nature bone. It is possible to modify the surface properties of titanium for enhanced surface biocompatibility. The main objective of the this study is to engineer a smart Ti-based prosthesis surface by self induced chemically modified titanium oxide nano-film by the chemical mechanical polishing process (CMP). This new process applied on bio-implants aims at significantly reducing the out-diffusion of Ti and other metallic impurities from prosthesis in contact with body fluids and tissue and simultaneously enhancing the surface mechanical, chemical and biological properties. CMP technique enables the growth of a thicker and denser self-protective native oxide on Ti and Ti alloy samples, while simultaneously inducing a controlled surface roughness. It is demonstrated that the Ti based dental implants with self-protective oxide induced surfaces help minimize chemical and bacterial reactivity in addition to Ti ion dissolution while promoting their biocompatibility through surface patterning. The studied self-protective oxide films can also be utilized for many additional applications including bio-sensors.

Results from the successful growth of high quality KH2PO4 (KDP) crystals with incorporated TiO2 anatase nanoparticles and the characterization of these crystals using several complementary methods are presented. Transmission and scanning electron microscopy have shown that the anatase nanoparticles were captured mainly by the pyramidal growth sector and, to a considerably lesser extent, by the prismatic growth sector. Energy dispersive x-ray analysis confirms that the growth layer stacks contain the TiO2 particles. Significant variation in the imaginary and real parts of the cubic nonlinear optical susceptibilities and refractive index changes at continuous wave excitation were found in prism and pyramid parts of pure KDP and KDP:TiO2 samples. The identified lines of electron paramagnetic resonance belong to four different centers FeA3+, FeB3+, CrR3+ and CrGB3+. From analysis of line intensities it was concluded that the concentration of non-controlled impurities in nominally pure KDP samples is several times larger than in KDP:TiO2, and that the concentration of non-controlled impurities in the prismatic part of the KDP:TiO2 boule is larger than in the pyramidal part.

There is great interest in improving TiO2’s photocatalytic activity in the visible portion of electromagnetic spectrum. Recent work has shown that co-doping mesoporous TiO2 microparticles with a transition metal and nitrogen, hereby designated as (M,N) TiO2, significantly increases its visible light absorption. However, the hydrothermal method used to produce the microparticles creates a wide distribution in the size of the microparticles, which could affect the absorption properties. Recently, it has become possible to produce monodisperse, mesoporous TiO2 microparticles with engineered sizes using a hybrid sol-gel/hydrothermal technique. Further, it has also been shown that the size of monodisperse TiO2 microparticles affects the the photocatalytic activity.

This study investigated whether using mondodisperse (M,N) TiO2 microparticles would further increase visible-light absorption for (M,N)TiO2. The first-row transition metals chosen for this study - Mn, Fe, Co, Ni, and Cu – have been characterized in the earlier (M,N) TiO2 UV-vis study, which was used as a baseline. The doping levels of the transition metals samples were set at the 2.5 percent level previously shown to be optimum for photocatalytic activity.

Nanostructured anatase TiO2 is a promising material for gas sensing and photocatalysis. In order to modify its catalytic properties, the lanthanide (Ln) ions Eu3+, Gd3+, Nd3+ and Yb3+ were precipitated on the surface of TiO2 nanoparticles (NPs) by hydrothermal treatment. Results from Raman spectroscopy and X-ray diffraction (XRD) measurements show that the anatase structure of the TiO2 nanoparticles was preserved after hydrothermal treatment. SEM and TEM show a heterogeneous distribution in size and a nanocrystallite morphology of the TiO2 NPs (∼ 14 nm in size) and EDX confirmed the presence of the Ln-ion surface doping after hydrothermal treatment. An increase in photoluminescence (PL) was observed for the Ln-surface-doped TiO2 NPs when measurements were made in forming gas (5% H2 + 95% Ar) at 520 °C. In contrast, the PL measurements made at room temperature did not show any noticeable difference in forming gas or in ambient air. Our temperature-dependent PL results obtained in different gas environments are consistent with modification of oxygen-vacancies and hole-defects due to a combination of hydrothermal treatment and surface Ln-doping.

Creation of high efficiency and safe air purification systems is the important task caused by their wide use in living quarters, medical institutions, industrial areas. The most effective cleaning systems are the ozone based ones which is formed as the result of the corona or barrier discharge. The main disadvantage of these purification systems is high concentration of ozone in discharge air. The paper concentrates on the study of catalytically active coatings on the basis of titanium dioxide for effective destruction of ozone inside air purification systems. It is shown that use of catalytically active coatings of collecting electrodes on the basis of titanium dioxide and manganese oxide allows to decrease significantly (20-50%) the ozone concentration at the filter exit. As the results of the researches the following requirements have been determined: -