Titanium Monoxide Research Articles

Spectral Emission Signatures from Cased High-Explosive Charges.

Spectroscopic signatures of cased high-explosive charge denotations are examined using emission spectroscopy with sub nanometer resolution. Eleven distinct case materials are investigated for atomic features of their major alloying elements. Molecular features of case material combustion products are also investigated for five case materials. Emission is monitored within the 275-425 nm range for atomic features and in the 310-755 nm range for molecular features. Major alloying elements with concentrations greater than 5% are generally detected through atomic emission. Al, Cu, Fe, Mg, Cr, Mn, Pb, and Ni are all detected in concentrations less than 5%. Undetected elements include Zn, Nb, Ta, and V. Molecular emission from aluminum monoxide, titanium monoxide, and CN is measured for aluminum alloy, titanium alloy, and carbon fiber cases, respectively.

Nitrogen-Doped Titanium Monoxide Flexible Membrane for a Low-Cost, Biocompatible, and Durable Raman Scattering Substrate.

The development of low-cost, biocompatible, and durable high-performance substrates is an urgent issue in the field of surface-enhanced Raman scattering (SERS). Herein, by reducing and exfoliating the TiO2-layered nanoplates in the gas phase, nitrogen-doped titanium monoxide (N-TiO) ultrathin nanosheets composed of 2-3 single layers with a thickness of only ∼1.2 nm are synthesized. Compared with pure TiO, the oxidation resistance of N-TiO is greatly improved, in which the oxidation threshold is significantly increased from 187.5 to 415.6 °C. The N-TiO ultrathin nanosheets are found to have strong surface plasmon resonance in the visible region. These ultrathin N-TiO nanosheets can be easily assembled into a large-scale flexible membrane and exhibit remarkable SERS effects. Moreover, this low-cost flexible SERS substrate combines the high durability of noble-metal substrates and the high biocompatibility of semiconductor substrates.

Hydrogen in nonstoichiometric cubic titanium monoxides: X-ray and neutron diffraction, neutron vibrational spectroscopy and NMR studies

Hydrogen-induced changes in the properties of transition-metal oxides have attracted much recent attention due to numerous applications of these materials including catalysis, H2 production, low-temperature H2 sensing, solar cells, and air purification. However, basic properties of hydrogenated titanium monoxides have not been investigated so far. In the present work, we report the results of the first studies of the crystal structure, vibrational spectra, and mobility of H atoms in TiO0.72H0.30 and TiO0.96H0.14 using X-ray diffraction (XRD), neutron powder diffraction, neutron vibrational spectroscopy, and nuclear magnetic resonance (NMR). The hydrogenated compound TiO0.72H0.30 is found to retain the disordered cubic B1-type structure of the initial titanium monoxide, where H atoms exclusively occupy vacancies in the oxygen sublattice. It has been revealed that hydrogenation of the disordered cubic TiO0.96 leads to the formation of the two-phase compound TiO0.96H0.14, where the disordered B1-type phase coexists with the monoclinic phase of Ti5O5 type with an ordered arrangement of vacancies. In both phases, H atoms are found to occupy only vacancies in the oxygen sublattice. The low-temperature inelastic neutron scattering spectra of TiO0.72H0.30 and TiO0.96H0.14 in the energy transfer range of 40–180 meV exhibit a single peak due to optical oxygen vibrations (centered on about 60 meV) and a broad structure at 90–170 meV due to optical H vibrations. The unusual width of this structure can be attributed to the broken symmetry of hydrogen sites in the titanium monoxides: because of the presence of vacancies in the titanium sublattice, the actual point symmetry of these sites appears to be lower than octahedral. Proton NMR measurements have revealed that both hydrogenated compounds are metallic; no signs of hydrogen diffusive motion in TiO0.72H0.30 and TiO0.96H0.14 at the frequency scale of about 105 s-1 have been found up to 370 K.

Titanium monoxide and titanium dioxide thin film formation by magnetron sputtering and its thermodynamic model

This work is devoted to the problem of the formation of titanium monoxide and dioxide by magnetron sputtering. Sputtering titanium in constant flows of oxygen and argon and constant magnetron power leads to the creation of equilibrium partial pressures of oxygen and titanium vapors. The conditions for the synthesis of nanocrystalline titanium monoxide at low temperatures were determined experimentally and substantiated by the thermodynamic method. An analysis is made by the method of minimizing the Gibbs free energy. We have obtained an expression for the ratio of the oxygen flow and the gas discharge power, the analysis of which makes it possible to determine the conditions for the formation of titanium oxide with a certain stoichiometric composition. The developed method for the analysis of equilibrium in the deposition chamber can be used to identify the conditions for the synthesis of other compounds that are important for practice, including oxides and chalcogenides, and the horizons of their use in nanoelectronics are constantly growing at the present time.

Formation Mechanism of Nitrogen-Doped Titanium Monoxide Nanospheres and Their Application as Sulfur Hosts in Lithium Sulfur Batteries

Formation Mechanism of Nitrogen-Doped Titanium Monoxide Nanospheres and Their Application as Sulfur Hosts in Lithium Sulfur Batteries

Joint metallothermic reduction of titanium and rare refractory metals of V group

The features of phase formation during the joint aluminothermic reduction of titanium, niobium, tantalum, vanadium from their oxides using methods of thermodynamic modeling, differential thermal and X-ray phase analysis were studied. Computer thermodynamic modeling made it possible to predict the optimal temperature conditions in the metallothermic process, composition and ratio of reagents in the charge, behavior of elements and sequence of phase formation. Thermodynamic calculations were supplemented by differential thermal studies using the combined scanning calorimetry method to identify the kinetic and thermochemical components of the process. An analysis of theoretical and experimental data allowed us to establish that the interaction of aluminum with titanium dioxide proceeds through the stage of titanium monoxide formation and features by the formation of TixAly intermetallic compounds of various compositions (TiAl3, TiAl, Ti2Al) depending on the Al and TiO2 ratio in the charge. When titanium dioxide is partially replaced by niobium, tantalum and vanadium oxides, the metallothermic process during interactions in the Al–TiO2–Nb2O5, Al–TiO2–Ta2O5 and Al–TiO2–V2O5 systems has a similar nature, enters the active phase once liquid aluminum appears, is accompanied by exothermic effects and features by the priority formation of titanium aluminides and binary and ternary intermetallic aluminum compounds with Group 5 rare refractory metals – AlNb3, Al3Nb, Al3Ta, Al3(Ti1–х, Taх), Al3(Ti0,8V0,2). The joint conversion of titanium dioxide and rare refractory metal pentoxides during the reduction process is carried out through sequential and parallel stages of the formation of simple and complex element oxides with low oxidation states.

Thermal behaviour of TiOy/HAp nanocomposites

The structural and microstructural characteristics and thermal behaviour of TiOy/HAp nanocomposite materials used for tissue engineering have been studied by differential and thermal gravimetric analyses (DTA–TGA), X-ray diffraction (XRD) phase analysis and scanning electron microscopy (SEM) methods. Substoichiometric TiO0.92 and superstoichiometric TiO1.23 were used in amounts of 10 and 20 wt %, respectively, to reinforce HAp. When the temperature increased as a result of interactions between the matrix and the introduced nanoparticles, titanium monoxide was oxidized to titanium dioxide. Comparing the DTA–TGA and XRD results allowed us to determine the temperature intervals of the beginning of the titanium valence variation and phase transitions occurring in the nanocomposites. The onset temperatures of HAp decomposition and TiOy oxidation depend on the initial stoichiometry of titanium monoxide and the composition of the reinforcing additive. The TiOy additives have a stabilizing effect on HAp. The effect of the additive stoichiometry on the interactions between the matrix and nanoparticles in the whole temperature range is shown.

An Analysis of the $B^{3}\Pi _{2} - X^{3}\Delta _{2}$ (0, 0) Band System of the TiO Molecule in Laboratory and Sunspot Spectra

The $B^{3}\Pi _{2} - X^{3}\Delta _{2}$ (0, 0) band system of the titanium monoxide (TiO) molecule was excited in a DC copper arc with a constant deviation spectrometer. The resulting spectrum has been analyzed using image J software. Relative intensity measurements of the P- and R-branch molecular lines of the (0, 0) band with rotational quantum ( $J$ ) numbering have been obtained. The measured intensity of rotational molecular lines and the $J$ numbering were used to estimate the excitation rotational temperature of the source emitting the spectrum of TiO molecules. Also the presence of TiO spectral lines of the $B^{3}\Pi _{2} - X^{3}\Delta _{2}$ (0, 0) band in the wavenumber region of 14 500 to 16 000 cm−1 has been confirmed in the umbral spectrum, from the atlases recorded at the National Solar Observatory using the Fourier transform spectrometer (FTS) of the McMath-Pierce Solar Telescope on Kitt Peak. The combined laboratory and sunspot spectral line measurements have been used to obtain the improved molecular structure parameters for the electronic states $B^{3}\Pi _{2}$ and $X^{3}\Delta _{2}$ of the TiO molecule. Using equivalent width measurements of well resolved and identified lines in the sunspot spectrum with known rotational quantum number, the effective rotational temperature was found to be $2555 \pm 780$ K. This proves the presence of TiO molecules in sunspot and other higher temperature astrophysical sources.

Effect of Stoichiometry and Ordering on the Microstructure of Titanium Monoxide TiO y.

The structure of titanium monoxide TiOy with different stoichiometries and long-range order degrees was studied by using X-ray diffraction, electron backscatter diffraction, Raman spectroscopy, and electron microscopy methods. It was established that the composition of the phases formed in annealed TiOy depends on the titanium monoxide stoichiometry. A new phase precipitation mechanism is proposed. The migration of vacancies in dislocations and their accumulation on grain boundaries play an important role in the formation of new phases. The stoichiometry of quenched titanium monoxide (TiOy) was found to affect the intensity of the peak associated with the vibrational mode of the Ti–O bond in Raman spectra.

Preparation of black titanium monoxide nanoparticles and their potential in electromagnetic wave absorption

In this work, black titanium monoxide (TiO) nanoparticles were synthesized by hydrogen assisted magnesium thermal reduction method from nanotube titanic acid (NTA) and their electromagnetic properties were investigated. The black TiO nanoparticles exhibited the optimal reflection loss of −37.7 dB at a thin absorbance layer of 1.2 mm in thickness, which showing a promising candidate in electromagnetic wave absorbing (EA). To explore the mechanism of EA, TiO nanoparticles prepared from the other two initiators (commercial grade TiO and P25 titanium dioxide) was used as a comparison. The results show that the crystalline structure and microscopic defects, which arouse from the formation of TiO in the hydrogen assisted process, affect the electromagnetic performance of Ti-O binary system significantly in addition to their intrinsic effects. We hope this study help to open a new way for the designing of high-performance EA materials.

Intermediates detection in the conversion of ethanol to butanol catalyzed by zirconium, cerium, titanium monoxide cations by inductively coupled plasma tandem mass spectrometry

Ethanol to butanol (ETB) process is an attractive route to upgrade abundant substrate into a product with superior properties in energy industry. For the mechanism research, the detection of intermediates is vital. In this paper, intermediates in ETB reaction catalyzed by monoxide ions [ZrO]+/[CeO]+/[TiO]+ were investigated by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). Some important organic small molecule intermediates, metal-adduct intermediates and their formation pathways were discussed to reveal the reaction mechanism in this research. Isotopic labelling experiments were also designed to ensure the existence of these intermediates.

Electrospun Nanofiber-Based Cathodes for Lithium-Sulfur Batteries

Lithium-Sulfur is a next generation battery chemistry that offers a theoretical capacity of 1,675 mAh/g, an order of magnitude higher than that of the currently used Li-ion battery cathodes. However, a serious challenge that has plagued the development of this technology is the dissolution and shuttle of intermediate polysulfides (Li2Sx, x=4-8) in the electrolyte resulting in loss of active material and rapid capacity fade during cycling. I will present two projects from my group both centred around Li-S batteries. In the first part of my talk, I will discuss our work on stabilization of titanium monoxide (TiO) nanoparticles in carbon nanofibers (CNF) through electrospinning and carbothermal processes and their unique bi-functionality – high conductivity and ability to bind polysulfides via Lewis acid-base interactions–as sulfur hosts. The developed 3-D TiO/CNF architecture with the inherent inter-fiber macropores of nanofiber mats provides a much higher surface area (~427 m2 g-1) and overcomes the challenges associated with the use of highly dense powdered Ti-based suboxides/monoxide materials, thereby allowing for high active sulfur loading among other benefits. The developed TiO/CNF-S cathodes exhibit high initial discharge capacities of ~1080 mAh g-1, ~975 mAh g-1, and ~791 mAh g-1 at 0.1C, 0.2C, and 0.5C rates, respectively with long-term cycling. Furthermore, free-standing TiO/CNF-S cathodes developed with rapid sulfur melt infiltration (~5 sec) eradicate the need of inactive elements viz. binders, additional current collectors (Al-foil) and additives. Using postmortem XPS and Raman analysis, this study reveals the presence of strong Lewis acid-base interaction between TiO (3d2) and Sx 2- through the coordinate covalent Ti-S bond formation. In the second part, I will discuss our work on in-situ infrared spectroelectrochemistry to understand redox mechanisms – a critical step for rational design of cathode systems for Li-S batteries. Specifically, I will discuss the use of sulfur-rich copolymers as active cathode materials and demonstrate in-situ FTIR with attenuated total reflection (ATR) to monitor polysulfide (PS) speciation (S x 2-, 2 ≤ x ≤ 8) and polymeric signature evolution while simultaneously discharging/charging a full battery coin cell.

Laser ablation of silicon monoxide and titanium monoxide in liquid: formation of mixed colloidal dispersion with photocatalytic activity

Silica–titania mixed oxides and composites have been extensively studied, whereas to the titanium monoxide (TiO) –silicon monoxide (SiO) counterparts has been devoted very little attention. Laser ablation of SiO and TiO in liquids is in according with literature completely unexplored. Here we report on Nd:YAG pulse laser ablation of SiO and TiO in ethanol which allows generation of SiO- and TiO-based nanoparticles and their agglomerates.Mixed SiO-TiO colloid has been prepared by simple mixing of ablatively prepared individual colloids in 1:1 volume ratio. Measurement of size distribution by Dynamic Light Scattering (DLS) determines sizes of 24.85 nm and 262.3 nm for SiO colloid, 494.8 nm for TiO colloid and 35.2 nm and 397.5 nm for mixed colloid. Zeta potential values suggest incipient instability for all measured systems. Morphology of the particles captured on Ta substrate by evaporation of ethanol was studied using Scanning Electron Microscopy (SEM). Round-shaped, oval, and sheet-like particles and their agglomerates have been observed. Raman spectroscopy of the mixed SiO-TiO colloid revealed multiphase structure consisting of anatase and/or rutile, crystalline and amorphous silicon and silica and crystalline and amorphous titanium silicide TiSi2. Formation of TiSi2 demonstrates unexpected low temperature disproportionation of SiO and TiO-based species and mutual reducing interactions. Catalytic activity of individual SiO and TiO colloids and of their mixture has been tested in terms of methylene blue (MB) degradation under the daylight. TiO-SiO mixture exhibits higher solar-light catalytic activity compared to individual colloids which could by explain by the presence of highly photocatalytic TiSi2. These results represent potential of SiO and TiO reducing interactions which are favorable for generation of photocatalytic materials for water remediation.

Ultrafine Titanium Monoxide (TiO1+x) Nanorods for Enhanced Sonodynamic Therapy.

Ultrasound (US)-triggered sonodynamic therapy (SDT) that enables noninvasive treatment of large internal tumors has attracted widespread interest. For improvement in the therapeutic responses to SDT, more effective and stable sonosensitizers are still required. Herein, ultrafine titanium monoxide nanorods (TiO1+x NRs) with greatly improved sono-sensitization and Fenton-like catalytic activity were fabricated and used for enhanced SDT. TiO1+x NRs with an ultrafine rodlike structure were successfully prepared and then modified with polyethylene glycol (PEG). Compared to the conventional sonosensitizer, TiO2 nanoparticles, the PEG-TiO1+x NRs resulted in much more efficient US-induced generation of reactive oxygen species (ROS) because of the oxygen-deficient structure of TiO1+x NR, which predominantly serves as the charge trap to limit the recombination of US-triggered electron-hole pairs. Interestingly, PEG-TiO1+x NRs also exhibit horseradish-peroxidase-like nanozyme activity and can produce hydroxyl radicals (•OH) from endogenous H2O2 in the tumor to enable chemodynamic therapy (CDT). Because of their efficient passive retention in tumors post intravenous injection, PEG-TiO1+x NRs can be used as a sonosensitizer and CDT agent for highly effective tumor ablation under US treatment. In addition, no significant long-term toxicity of PEG-TiO1+x NRs was found for the treated mice. This work highlights a new type of titanium-based nanostructure with great performance for tumor SDT.

Stability of vacancy-free crystalline phases of titanium monoxide at high pressure and temperature

There have existed for a long time a paradigm that TiO phases at ambient conditions are stable only if structural vacancies are available. Using an evolutionary algorithm, we perform an ab initio search of possible zero-temperature polymorphs of TiO in wide pressure interval. We obtain the Gibbs energy of the competing phases taking into account entropy via quasiharmonic approximation and build the pressure-temperature diagram of the system. We reveal that two vacancy-free hexagonal phases are the most stable at relatively low temperatures in a wide range of pressures. The transition between these phases takes place at 28 GPa. Only above 1290 K at ambient pressure the phases with vacancies (B1-derived) become stable. In particular, the high-pressure hexagonal phase is shown to have unusual electronic properties, with a pronounced pseudo-gap in the electronic spectrum. The comparison of DFT-GGA and GW calculations demonstrates that the account for many-body corrections significantly changes the electronic spectrum near the Fermi energy.

Structure and reactivity of highly reduced titanium oxide surface layers on TiO2: A first-principles study.

Titanium oxide structures featuring highly reduced TiOx films on top of nearly stoichiometric TiO2 hold promise for applications ranging from photocatalysis to resistance switching devices. Here, we focus on titanium monoxide (TiO) layers on anatase TiO2 (001) and use first principles calculations to investigate their structure and properties as well as their interface with liquid water. We find that only a single TiO layer can grow epitaxially on anatase (001) and subsequent growth leads to the formation of TiO islands. The TiO layers decrease the work function and enhance the surface conductivity in comparison to pure anatase, two features that can improve the TiO2 performance in photocatalytic hydrogen evolution but are thermodynamically unstable relative to pure TiO2 in humid/aqueous environment. Furthermore, first principles molecular dynamics simulations of the TiO (001)-water and anatase (001)-water interfaces show that unlike the multilayer structure of interfacial water on the anatase surface, a very dense and tightly packed first water layer is present on the surface of TiO, which could represent the first stage of partial surface reoxidation.

Study of the absorption spectrum of the thin film of titanium monoxide in the mid-wavelength IR range

The paper presents experimental study of IR absorbance of the thin TiO film (with the thickness of 600 nm) on the glass substrate. The titanium monoxide (TiO) film was prepared with the ion-beam scattering. The film was characterized by XRD, FTIR, SEM etc. IR absorption spectra for the film and the substrate were measured. It was shown that the average absorbance Ā of the pure glass substrate is Ā ≈ 0.08 in the wavelength range λ = 2.5 … 15 μm. For the TiO film it was obtained that Ā ≈ 0.38 in the same λ range.

Effect of Oxidizing Atmosphere on the Surface of Titanium Dental Implant Material

Direct oxidation is a simple and effective method for titanium surface treatment. In this research, a titanium sample was directly oxidized at the high temperature in two different atmospheres, air and pure oxygen, to obtain better atmosphere for titanium surface treatment. The results of the Raman spectroscopy indicated that in both atmospheres, the rutile bioactive phase (TiO2) has been formed on the titanium surface. The results of X-ray diffraction (XRD) also revealed that the surface of oxygen-treated sample was composed of the rutile phase and titanium monoxide (TiO), while at the surface of the air-treated sample, the rutile phase and titanium dioxide had been formed. Further, the results of Field Emission Scanning Electron Microscopy (FE-SEM) showed that by the surface treatment of titanium in both atmospheres, some micro-features including cracks thinner than 30 nm were formed on the surface. Because of more apatite forming ability and fewer water contact angle and more L-929 cell attachment of the air-treated titanium, it seemed that air, in comparison to the pure oxygen, is more promising atmosphere for the direct oxidation of titanium and improving its biofunctionalization.

Pressure-induced structural phase transition and vacancy filling in titanium monoxide TiO up to 50 GPa

Vacancy engineering can effectively modulate the optical and electronic properties of metal oxides. Here, we demonstrate that high-pressure could be a clean strategy to tune the vacancies in oxides with a high cationic vacancy content. By combining in situ synchrotron x-ray diffraction, Raman scattering, and charge transport measurements in a diamond anvil cell, we systematically study the structure and electrical properties of TiO with ∼16% ordered vacancies up to 50.2 GPa at room temperature. The monoclinic TiO transforms to the cubic phase at ∼37.8 GPa. After decompression to ambient conditions, the cubic phase survives. The vacancies are partially filled and become disordered with a concentration of approximately 12.5%. The charge transport of TiO at high pressure exhibits a metal-insulator transition, which originates from the ordered to disordered transition of vacancies under pressure. Molecular dynamics simulations suggest that the vacancies enhance the mobility of atoms in the lattice under pressure and lead to the pressure-induced amorphization and recrystallization.

Size effect in nonstoichiometric titanium monoxide and vanadium carbide nanocrystals measured by positron lifetime spectroscopy

A size effect in nonstoichiometric titanium monoxide TiOy and vanadium carbide VCy nanocrystals containing high concentrations of structural vacancies was detected by electron-positron annihilation. The effect consists of a considerable increase in the positron lifetime with the specific surface area. An analysis of the intensity of a long lifetime surface component in the positron annihilation spectra and the average positron lifetime for different nonstoichiometric compounds indicated a universal character of the observed size effect.