Incorporation Of Titanium Research Articles

Synthesis and Hydrogen Desorption Properties of Mg1.7Al0.15Ti0.15Ni-CNT Nanocomposite Powder

In this research, the effects of nanocrystallization and incorporation of aluminum, titanium, and carbon nanotubes (CNTs) on hydrogen desorption behavior of Mg2Ni alloy were investigated. Toward this purpose, nanocrystalline Mg2Ni intermetallic compound with average grain size of 20 nm was prepared by ball milling of elemental magnesium and nickel powders. Mg2Ni powder was then ball milled with aluminum and titanium powders for 20 h to dissolve these elements into the Mg2Ni structure, leading to the formation of Mg1.7Al0.15Ti0.15Ni compound. The elemental x-ray mapping analysis revealed the uniform dissolution of aluminum and titanium inside the Mg2Ni structure. Mg2Ni and Mg1.7Al0.15Ti0.15Ni compounds were further ball milled with 3 wt.% CNT for 5 h. The high-resolution field emission scanning electron microscopy and transmission electron microscopy revealed that CNTs have retained their tubular shape after ball-milling process. The hydrogen desorption properties of the samples were identified using a Sieverts-type apparatus at 473 K. The Mg2Ni, Mg2Ni-CNT, and Mg1.7Ti0.15Al0.15-CNT samples showed the desorbed hydrogen of 0.17, 0.25, and 0.28 wt.% after 1 h, respectively, indicating 47 and 65% increase in the hydrogen desorption capability of Mg2Ni via CNT addition and co-presence of aluminum-titanium-CNT. The direct hydrogen diffusion through CNTs and development of local atomic distortion due to substitution of magnesium atoms by aluminum and titanium appears to be responsible for enhancement of desorption behavior of Mg1.7Al0.15Ti0.15-3 wt.% CNT.

Indene epoxidation over titanium modified MCM-41 mesoporous materials

The current research is focused on the testing of titanium modified MCM-41 in indene epoxidation. Two preparation methods of Ti catalysts with mesoporous structure were tested, namely grafting of titanium on prepared MCM-41 (Ti/MCM-41/gr) and incorporation of titanium into the structure of MCM-41 by co-gelification method (Ti-MCM-41/cg). The tested catalysts exhibited high surface area, well-defined regular structure and narrow pore size distribution of mesopores and therefore represent potential good quality catalytic systems. The successful preparation of catalysts was confirmed by wide range of characterization methods (XRF, XRD, physical adsorption of N2, SEM, UV–Vis and FTIR). The catalytic activity of the prepared Ti catalysts was evaluated in indene epoxidation. The optimization of reaction conditions was performed using two types of oxidizing agents—aqueous solution of tert-butyl hydroperoxide and solution of tert-butyl hydroperoxide in decane. The prepared catalytic systems were successfully used for preparation of 1,2-epoxyindane with high yield (83 %) and the possibility of catalyst regeneration was proved.

Carbon nanotube/ polypyrrole nanofibers core–shell composites decorated with titanium dioxide nanoparticles for supercapacitor electrodes

The development of new materials for hybrid supercapacitors requires the adequate combination of pseudocapacitance and electrical double layer capacitance, morphology, high surface area and low mass density of electrodes. In this work, we have explored a simple and low cost composite based on incorporation of titanium dioxide/single walled carbon nanotube complex during polymerization of hollow nanotubes of polypyrrole. The resulting composite is characterized by superior electrical properties (high conductivity) and improved electrochemical response. The optimization in the relative concentration of components of ternary composite results in a capacitance of 282 Fg−1 and specific energy density in order of 1.0 Wh kg−1 which is a result of synergistic interaction of components during polymerization of polymeric hollow nanotubes and core/shell structures of SWCNTs/polypyrrole decorated with titanium dioxide nanoparticles.

Mechanisms of Oxide Scale Formation on Ferritic Interconnect Steel in Simulated Low and High pO2 Service Environments of Solid Oxide Fuel Cells

The Laves phase strengthened ferritic steel Crofer 22 H has recently been proposed as construction material for interconnects in solid oxide fuel cells (SOFCs). In the present study, the oxidation kinetics of Crofer 22 H at 800 °C was compared with that of a Mn-free batch during exposure in air and Ar–H2–H2O, the latter simulating the anode gas of a SOFC. Main emphasis was put on studying the oxidation mechanisms of Crofer 22 H during the early stages of isothermal reaction as well as during long-term discontinuous exposure. Differences in oxidation mechanisms in air and simulated anode gas (SAG) were defined. Oxidation rates for Crofer 22 H in air were found to be initially slower than in SAG, but the opposite effect was observed after longer exposure times. This effect of atmosphere composition on the oxidation rate is shown to be governed by the time dependent extent to which the inner chromia scale layer is covered by an outer Cr/Mn spinel layer. In both test gases the minor addition of silicon to Crofer 22 H resulted in internal silica formation during the very early stages of oxidation; this effect vanished after longer exposure times. Incorporation of titanium in the scale differed for the two test atmospheres because the oxygen partial pressure affects titanium solubility in chromia and especially the spinel phase.

Templated fabrication of hierarchically porous Fe–Ti bimetallic solid superacid for efficient photochemical oxidation of azo dyes under visible light

• Hierarchically porous S–Fe 2 − x Ti x O 3 was prepared by critic acid templated method. • Cooperative effect of titanium and sulfate created lots of Lewis acid sites. • Fe–Ti bimetallic solid superacid widened the pH range to 10.0 in Fenton reaction. • Light with wavelength 450–595 nm had significant effect on activity of S–Fe 2 − x Ti x O 3. • Favorable synergetic effect of acid sites and photo improved catalytic activity. A new hierarchically porous solid superacid SO 4 2 - /Fe 2 − x Ti x O 3 was prepared by way of facile citric acid templates and sulfuric acid impregnating strategy. The prepared catalyst exhibited high activity and stability for activation of H 2 O 2 as higher than 90% of organic dyes were decomposed in 30 min at neutral pH under visible light irradiation. UV–vis spectrum and ion chromatography were used to investigate the degradation pathway of dyes. By characterizations, it was found that incorporation of titanium and sulfur had a significant effect on properties and structure of the solid. Large numbers of strong Lewis acid sites were produced on the surface due to cooperative effect of Ti and S, which made significant contributions toward high activity in strong alkaline condition (pH 10.0). Meanwhile, the transition metal doping and oxygen vacancies generation can narrow the band gap of the catalyst and efficiently enhance visible light photocatalytic performance. It was also observed that high catalytic activity can hardly be achieved if acid functionalization or light irradiation was applied individually. This was clearly evidenced that the synergetic effect of acid sites and photo-induced electrons transfer played a crucial role in Fenton reaction, which may be attributed to that the appearance of acid sites (Lewis and Brønsted acidic center) was favorable for the separation of photo-induced electrons and holes and suppressed charge recombination.

Titanium incorporation into hematite photoelectrodes: theoretical considerations and experimental observations

A thorough literature review and the investigation by soft X-ray absorption spectroscopy at synchrotron facilities of Ti-Hematite photoelectrodes are provided.

Montmorillonite intercalated with SiO2, SiO2-Al2O3 or SiO2-TiO2 pillars by surfactant-directed method as catalytic supports for DeNOx process

AbstractThe intercalation of natural montmorillonite with SiO2, SiO2-Al2O3 or SiO2-TiO2 pillars by the surfactant-directed method resulted in the formation of high surface area porous materials; these were tested as catalytic supports for the process of selective catalytic reduction of NO (DeNOx). The incorporation of titanium or aluminium into the structure of the silica pillars significantly increased the surface acidity of the clay samples. Iron and copper were deposited onto the surface of the pillared clays mainly in the form of monomeric isolated cations and oligomeric metal oxide species. The contribution of the latter species was higher in the clay intercalated with SiO2-TiO2 pillars than in the samples modified with SiO2 and SiO2-Al2O3 pillars. The pillared clay-based catalysts were active in the DeNOx process but, in this group, the best results were obtained for the clay intercalated with SiO2-TiO2 pillars and doped with iron and copper. The catalytic performance of the samples is discussed in respect of their surface acidity and active forms of transition metal species deposited.

Zn–Ni/nano-TiO2 composite electrodeposits: surface modifications and protective properties

Zn–Ni composite coatings were obtained by electrochemical co-deposition of TiO2 nano-particles (mean diameter 21 nm). Zn–Ni alloy coating was also produced under the same experimental conditions for comparison. The surface morphology, crystallographic structure, and the grain size of the deposits were investigated, along with the percentage of the embedded nano-particles in Zn–Ni matrix, as a function of concentration of TiO2 nano-particles in the bath. As the titania incorporation percentage is increased, a grain refinement in the nanometer region was revealed followed enhanced microhardness values and an improvement of the content of the nickel in the alloy. Annealing of all coatings at 200 °C revealed the crystallization of the matrix accompanied by a decrease of microhardness followed by stability for 24 h. The corrosion behavior of Zn–Ni/nano-TiO2 composite coatings with various amount of particle content was mainly studied by electrochemical impedance spectroscopy in 3 % NaCl. It was seen that Zn–Ni/nano-TiO2 composite coatings exhibited higher corrosion resistances comparing to Zn–Ni alloy coating and corrosion protection improved with increasing nano-TiO2 in coatings.

Improvement of Thermal Stability of Nickel Silicide Using Co-sputtering of Ni and Ti for Nano-Scale CMOS Technology

In this paper, a thermally stable nickel silicide technology using the co-sputtering of nickel and titanium atoms capped with TiN layer is proposed for nano-scale metal oxide semiconductor field effect transistor (MOSFET) applications. The effects of the incorporation of titanium ingredient in the co-sputtered Ni layer are characterized as a function of Ti sputtering power. The difference between the one-step rapid thermal process (RTP) and two-step RTP for the silicidation process has also been studied. It is shown that a certain proportion of titanium incorporation with two-step RTP has the best thermal stability for this structure.

Precursor adsorption efficiency of titanium tetra isopropoxide in the presence of a barium β-diketonate precursor

Barium titanate is a promising candidate for integrated photonic application due to its high electro-optic coefficient; therefore the need arises for a suitable deposition technique which provides high film quality at low temperatures (below 500°C) and reasonable growth rates. We report on combinatorial high vacuum chemical vapor depositions of titanium(IV) tetra isopropoxide and barium hexafluoroacetylacetonate (hfa)–tetraglyme on silicon substrates aiming at the deposition of barium titanate. The barium precursor was synthesized and characterized regarding its evaporation kinetics. Co-depositions of both precursors were carried out in the absence and presence of reactive gas partners such as H2, H2O, O2 and O3. Plain substrates deposited in the absence of ozone, however, do not show any titanium incorporation. We call this phenomenon obviating precursor interaction. Elongated masking structures were designed and manufactured on silicon substrates to modify locally the precursor impinging rate of one of both precursors to study the nature of this obviating behavior. It was found, that the blocking results from a reduced sticking coefficient, i.e. a fast desorption of the precursor prior to decomposition. When adding ozone, distinct, sharply separated regions were identified on the substrate, which we separate, according to their chemical composition and morphology, into TiO2, Ba-containing and barium and titanium mixed deposit. We found that the transition between TiO2 and Ba-deposit is dependent on the titanium to barium precursor impinging ratio. Depending on the barium precursor flux, the third region of mixed deposition of barium and titanium forms in the Ba deposit. The mixed deposit indicates a promising starting point for a combinatorial high vacuum chemical vapor deposition optimization to evaluate the feasibility of a high quality barium titanate film by this technique.

Multi-step Dealumination and Incorporation of Titanium into the Framework of Natural Mordenite toward a Titanosilicate Catalyst

Multi-step Dealumination and Incorporation of Titanium into the Framework of Natural Mordenite toward a Titanosilicate Catalyst

The effect of titanium incorporation on the thermal stability of phenol-formaldehyde resin and its carbonization microstructure

A new titanium modified phenolic resin (Ti–PF) was prepared by using tetraisopropyl titanate, phenol and formaldehyde with mild and friend reaction condition. The structure of the modified resin was demonstrated by means of FT-IR spectra. The titanium modified resin is soluble only in a few solvents such as DMF, DMAc, DMSO, but exhibits poor solubility in most universal solvents. The thermal degradation behavior of the Ti–PF was studied by thermal gravimetric (TG) method. Compared with the unmodified resin (PF), the temperature at the maximum decomposing rate of the Ti–PF increases by 43 °C and its charring yield enhances by 11 percent. The carbonized products of PF (C–PF) and Ti–PF (C–Ti–PF) were further investigated by X-ray diffraction and Roman spectroscopy, respectively. The analysis indicates that the incorporation of titanium into carbon lattice results in an increase of crystallite height and decrease of interlayer spacing. Titanium modified PF becomes much more ordered with a d002 of 0.3572 nm as compared to that of 3.7811 nm for C–PF. And the crystal size of C–Ti–PF increases to 4.37 nm, 2.13 nm larger than that of C–PF. In addition, the ID/IG value of C–Ti–PF decreases from 2.85 (C–PF) to 2.62. The results prove that the incorporation of titanium exhibited obvious effects on improving thermal stability of the phenolic resin and on promoting its graphite crystallite.

Influence of Ti addition on boehmite-derived aluminum silicate aerogels: structure and properties

Aluminosilicate aerogels offer potential for extremely low thermal conductivities at temperatures greater than 900 °C, beyond where silica aerogels reach their upper temperature use limits. Aerogels have been synthesized at two Al:Si ratios, a 3Al:1Si mullite composition, and an 8Al:1Si alumina rich composition. Boehmite (AlOOH) is used as the Al source, and tetraethoxysilane as the Si precursor. The influence of Ti as a ternary constituent, introduced through the addition of titanium isopropoxide in the sol–gel synthesis, on aerogel morphology and thermal properties is evaluated. Four different boehmite precursor powders are evaluated. Morphology, surface area and pore size, and thermal transformation vary with the crystallite size of the starting boehmite powder, as does incorporation of titanium and evolution of Ti-containing crystalline phases. The addition of Ti influences sol viscosity, gelation time, surface area and pore size distribution, as well as phase formation on heat treatment.

Incorporation of lead and titanium into a porous alumina membrane during Pb(Zr0.52Ti0.48)O3 nanotube synthesis

We report the identification and characteristics of lead aluminate (Pb2Al2O5 or PbAl12O19)/aluminum titanate (Al2TiO5) formed as a result of the interaction between a Pb(Zr0.52Ti0.48)O3 (PZT) precursor and a porous alumina membrane (PAM) during PZT nanotube synthesis. The surface morphology and composition of PZT nanotubes were examined as a function of the etching time and annealing temperature, and the diffusion of elements over nanometer length scales during PZT nanotube formation was investigated based on analysis using field emission transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive x-ray microscopy. As the annealing temperature increased, the volume of lead aluminate/aluminum titanate increased, suggesting that considerable diffusion of Pb and Ti occurred and, in turn, dramatically affected the nanotube characteristics. The diffusion of Pb and Ti was clearly evident, resulting in the formation of a distinct lead aluminate/aluminum titanate at the PZT nanotube/PAM interface.

Curing of liquid polydimethylsiloxanediols with trialkoxytitanium borates

Curing of SKTN liquid siloxane rubbers (polydimethylsiloxanediols) with trialkoxytitanium borates, leading to incorporation of titanium and boron atoms into vulcanized polysiloxane molecules and to formation of the corresponding network polyelementoorganosiloxanes, was studied. The kinetics of curing of liquid polydimethylsiloxanediols with trialkoxytitanium borates was examined. The effective rate constants of curing and the activation energy of the reaction were calculated.

Effects of titanium incorporation on phase and electrochemical performance in LiFePO4 cathode material

Ti-incorporated LiFe1−xTixPO4 (0≤x≤0.2) samples have been prepared via a two-step solid-state reaction route. The samples have systematically been investigated with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), cyclic voltammetry (CV) and charge/discharge measurements. The incorporation of Ti in LiFePO4 significantly enhances the electrochemical performance; the carbon-coated LiFe0.9Ti0.1PO4 sample shows the best performance. It is confirmed that LiFe1−xTixPO4 with x≤0.05 are of single phase while those with 0.07≤x≤0.2 contain impurity phases: LiTi2(PO4)3 and TiP2O7. The impurities influence not only the electronic conductivity, but also the total specific capacity. Appropriate amount of titanium incorporation is favorable for the improvement in electrochemical performance.

Heterogeneous UV/Fenton degradation of TBBPA catalyzed by titanomagnetite: Catalyst characterization, performance and degradation products

Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant, could negatively affect various aspects of mammalian and human physiology, which triggers effective techniques for its removal. In this work, the degradation characteristics of TBBPA in heterogeneous UV/Fenton reaction catalyzed by titanomagnetite (Fe3−xTixO4) were studied. Batch tests were conducted to evaluate the effects of titanomagnetite dosage, H2O2 concentration and titanium content in magnetite on TBBPA degradation. In the system with 0.125 g L−1 of Fe2.02Ti0.98O4 and 10 mmol L−1 of H2O2, almost complete degradation of TBBPA (20 mg L−1) was accomplished within 240 min UV irradiation at pH 6.5. The titanium incorporation obviously enhanced the catalytic activity of magnetite. As shown by the XRD and XANES results, titanomagnetite had a spinel structure with Ti4+ occupying the octahedral sites. On the basis of the degradation products identified by GC-MS, the degradation pathways of TBBPA were proposed. TBBPA possibly underwent the sequential debromination to form TriBBPA, DiBBPA, MonoBBPA and BPA, and β-scission to generate seven brominated compounds. All of these products were finally completely removed from reaction solution. In addition, the reused catalyst Fe2.02Ti0.98O4 still retained the catalytic activity after three cycles, indicating that titanomagnetite had good stability and reusability. These results demonstrated that heterogeneous UV/Fenton reaction catalyzed by titanomagnetite is a promising advanced oxidation technology for the treatment of wastewater containing TBBPA.

Structural incorporation of titanium and/or aluminum in layered silicate magadiite through direct syntheses

Synthesized inorganic layered magadiite containing structurally incorporated titanium and aluminum was obtained through hydrothermal procedures. The effects associated with reaction time and amount of metal used in the crystallization process yielded mostly pure and crystalline samples with 1.0% of aluminum after 36 h at 423 K. Amounts up to 4.0 and 2.0% for aluminum and titanium were successfully incorporated in the magadiite structure without co-crystallization of other phases. A higher amount of metal source or longer crystallization times led to formation of crystobalite and trydimite phases, detected by X-ray diffraction (XRD) and scanning electron microscopies. Metal incorporation slightly improved the thermal resistance of the precursor layered magadiite. Replacement of both atoms in the silicon network was examined by spectroscopy analysis. The changes in tetrahedral-oxygen-tetrahedral structural shape vibrations caused the appearance of the Ti–O–Si band at 960 cm−1. Nuclear magnetic resonance in the solid state demonstrated tandem octahedral and tetrahedral aluminum sites. Another structural feature related to titanium incorporation was observed through diffuse reflectance with UV–Vis and X-ray photoelectron spectroscopies, which distinguish crystalline and amorphous TiO2 and titanium incorporated into the silica network. Metal quantification by energy dispersive spectroscopy and X-ray fluorescence (XRF) was also followed with multivariate analysis, including principal component analysis (PCA) and partial least squares (PLS). The PCA methodology procedure clearly gives information to separate sample groups, in agreement with XRD results, which becomes a valuable feature obtained for the first time for these kinds of materials.

Ethylene polymerization on polymer supported Ziegler-Natta catalyst

Poly(styrene-co-methyl methacrylate) has been used as a support for titanium based Ziegler–Natta catalyst. We have prepared three polymer supported catalysts by varying the weight ratio of TiCl4 and polymer to perform the ethylene polymerization. Triethylaluminium (TEA) is used as cocatalyst. Catalysts have been characterized by XPS, FT-IR, UV-visible spectroscopy, XRD, pH meter, TGA and SEM-EDX. The catalysts are found to be stable upto 100 °C. Density functional theory (DFT) has been used to elucidate the structure of TiCl4 and the polymer supported complex. All these spectroscopic analysis and density functional study confirm the incorporation of titanium into the polymer matrix. The catalytic activity is found to be in the range of 0.6–1.01 kg of polyethylene (PE)/g Ti/h and the catalytic activity depends on the optimum level of Ti content. The molecular weight ( $$ \overline {{M_w}} $$ ) of PE is in the range of 237,300–275,600 g/mol. Present study also reports the stability and storability of the catalysts.

Titanium-containing bioactive phosphate glasses

The use of biomaterials has revolutionized the biomedical field and has received substantial attention in the last two decades. Among the various types of biomaterials, phosphate glasses have generated great interest on account of their remarkable bioactivity and favourable physical properties for various biomedical applications relating to both hard and soft tissue regeneration. This review paper focuses mainly on the development of titanium-containing phosphate-based glasses and presents an overview of the structural and physical properties. The effect of titanium incorporation on the glassy network is to introduce favourable properties. The biocompatibility of these glasses is described along with recent developments in processing methodologies, and the potential of Ti-containing phosphate-based glasses as a bone substitute material is explored.