Influence of TiO2 Nanoparticles on Liquid Crystalline, Structural and Electrochemical Properties of (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine

Organic–inorganic hybrids based on liquid crystalline symmetrical imine (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine (AZJ1) with two aliphatic chains and TiO2 nanomaterials were obtained and investigated taking into account thr crystallographic form of titanium dioxide i.e. anatase versus rutile. The type of TiO2 influences the mesomorphic properties of imine AZJ1, as observed by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques. Fourier-Transform Infrared Spectroscopy (FT-IR) was used to investigate the interactions of oxygen vacancies located on the TiO2 surface with the studied AZJ1 imine together with studying the influence of temperature. Both imine:TiO2 anatase versus rutile hybrids possessed the highest occupied molecular orbital (HOMO) levels of about −5.39 eV (AZJ1:anatase) and −5.33 eV (AZJ1:rutile) and the lowest unoccupied molecular orbital (LUMO) levels of about −2.24 eV. The presence of TiO2 in each hybrid did not strongly affect the redox properties of imine AZJ1. Organic devices with the configuration of ITO/TiO2/AZJ1 (or AZJ1:TiO2 anatase versus rutile)/Au were fabricated and investigated in the presence and absence of visible light irradiation with a light intensity of 93 mW/cm2. Finally, to analyze defects in the constructed organic devices we used thermal imaging and atomic force microscopy (AFM). The addition of TiO2 in both crystallographic forms has a positive influence on layer-forming properties that manifests itself as a very homogenous heat distribution for the whole sample.

Characteristic of Oxide Layers Obtained on Titanium in the Process of Thermal Oxidation

Thermal oxidation in air may be one method to improve the properties of titanium and its alloys through its influence on the structure and properties of the material’s surface layer. This paper presents a description of oxide layers obtained on the surface of Grade 2 titanium as a result of oxidation at temperatures of 600 and 700°C. On the basis of kinetic curves, it was found that the intensity of oxide layer growth increased with oxidation temperature. Studies of the surface morphology of oxide layers showed that the size of the formed oxide particles was greater following oxidation at 600°C. The obtained layers were subjected to X-ray phase analysis and microhardness measurements. Irrespective of oxidation temperature, the scale consisted of TiO2 oxide in the crystallographic form of rutile and of Ti3O oxide. The hardness of oxide layers amounted to around 1265 HV and was more than 4 times higher compared to the material in i ts initial state.

Physicochemical Study of Photocatalytic Activity of TiO2Supported Palygorskite Clay Mineral

This study deals with the influence of physicochemical parameters, namely, the photocatalyst loading, dye concentration, and pH of polluted solutions, on the degradation efficiency of Orange G (OG) solutions containing TiO2nanoparticles supported on palygorskite clay mineral (TiO2-Pal). The TiO2photocatalyst attached to natural palygorskite fibers was elaborated by colloidal sol-gel route. It exhibits the anatase structure that is the most photoactive crystallographic form. The highest performances of supported photocatalyst on OG degradation were found using an optimum amount of TiO2-Pal around 0.8 g·L−1, which corresponds properly toca. 0.4 g·L−1of TiO2. This amount is interestingly lower than the 2.5 g·L−1generally reported when using pure unsupported TiO2powder. The photodegradation rate increases by decreasing OG initial concentration, and it was found significantly higher when the OG solution is either acidic (pH<4) or basic (pH≈11). For OG concentrations in the range5×10-6– 5×10-4 M, the kinetic law of the OG degradation in presence of TiO2-Pal is similar to that reported for unsupported TiO2nanopowder. It follows a Langmuir-Hinshelwood model with a first-order reaction and an apparent rate constant of about2.9×10-2 min−1.

Building 3D materials from adjustable 2D-units; towards the Design of new Bi-based compounds

ABSTRACTIn the Bi2O3-MO-P2O5 diagram, on the basis of previous compounds based on 2D-ribbon like units, we have predicted and prepared the infinite term. It contains [Bi2O2]2+ planes arranged within a never-observed crystallographic form. In this series, the ribbons-like units are polycations built on the linkage of n O(Bi,M)4 tetrahedra along their width and infinite in a perpendicular dimension. Hence, this novel form completes the continuous series of analogue compounds, whose building units now extend from the single chain to the infinite plane, via a number of discrete n values (2,3,4,5,6,7,8,9,10,11). The presented materials of formulae Bi4MP2O12 (M= Zn and Mg) roughly show the same crystal structure. However different arrangements of the groups located between the [Bi2O2]2+ planes are at the origin of a complex superstructure in the case of the zinc compounds.

OBSERVATION OF QUANTUM OSCILLATIONS IN FOUR-LAYER BaRuO3

Well characterized single crystals of the four layer crystallographic form of BaRuO3 were studied at low temperatures (20 < T < 850 mK) and high magnetic fields (0 < H < 30 T). Quantum oscillations have been observed via the Shubnikov - de Haas and de Haas - van Alphen effects. In marked contrast, BaRuO3 with the nine-layer structure shows no similar behavior, suggesting a substantial change in the Fermi surface or quasi-particle relaxation times. The quantum oscillations provide insight into the ground state which, like those of other layered ruthenates, is characteristically sensitive to electron-lattice coupling. This observation is significant in that it represents the first example of quantum oscillations in a non-Ruddlesden–Popper type ruthenate and provides some insight into the Fermi surface even though a psuedo-gap is evident in other studies.