Titanyl Nitrate Research Articles

Development and Catalytic Application of Palladium Doped Titania (Ti0.98Pd0.02O2) Through Low Temperature Solution Combustion Method

The objective of the research was mainly focused on development of TiO2 and Palladium doped TiO2 by low temperature solution combustion method using glycine as fuel. Palladium substituted Titania (Ti0.98Pd0.02O2) was prepared by taking stoichiometric amounts of titanyl nitrate, palladium chloride and glycine by solution combustion method. The accurate size and morphology of the doped metal oxide was studied Scanning electron microscope (SEM). The phase composition of the palladium substituted Titania (Ti0.98Pd0.02O2) was confirmed from powder X-ray Diffractometer (PXRD). The functional groups are analyzed by Fourier transfer infrared spectroscopy. The doped metal oxide shows superior catalytic performance.

Characterization of SrCo1.5Ti1.5Fe9O19 hexagonal ferrite synthesized by sol-gel combustion and solid state route

Co-Ti co-substituted SrM hexagonal ferrite (SrCo1.5Ti1.5Fe9O19) was synthesized by sol-gel combustion and solid state route. The effects of sources of TiO2 raw materials; titanium tetra-isopropoxide (TTIP) and titanyl nitrate (TN) on the phase formation behavior and properties of the ferrite were studied. The thermal decomposition behavior of the gel was studied using TG-DSC. The phase formation behavior of the ferrite was studied by using X-ray powder diffraction and FTIR analysis. Phase formation was comparatively easier in the TN-based sol-gel process. The morphology of powder and sintered ferrite was investigated using scanning electron microscope. Magnetic properties like magnetization, coercivity, permeability, tan δµ and dielectric properties were investigated. The ferrite synthesized by sol-gel based chemical route showed higher saturation magnetization, permeability and permittivity compared to the ferrite synthesized by solid state route.

Preparation of BaTiO3 nanopowders by the solution combustion method

Barium titanate was synthesized by the method of exothermal combustion in solutions using barium nitrate, titanium dioxide (TiO2) and titanyl nitrate (TiO(NO3)2) as sources of titanium and barium and reducing agents such as glycine (C2H5NO2), carbamide (СН4N2O) and glycerol (C3H5(OH)3). In an effort to form a barium titanate phase, the materials synthesized using titanium dioxide were subjected to additional calcination at 800°С. With titanyl nitrate the use of glycine and carbamide enabled carrying out a single-step synthesis of barium titanate. The obtained materials have pseudo-cubic lattice and are characterized by high stability of properties in a wide range of temperatures and frequencies of the electromagnetic field.

ChemInform Abstract: V‐Doped Titanium Mixed Oxides as Efficient Catalysts for Oxidation of Alcohols and Olefins.

V/TiO2 nanoparticles were synthesized by a one-pot solution combustion method using ammonium metavanadate and titanyl nitrate as a source of vanadium and titanium, respectively. Atomic absorption spectroscopy (AAS), FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the physicochemical properties of this compound. This compound shows efficient catalytic reactivity for epoxidation of olefins and oxidation of alcohols in the presence of H2O2 as an oxidant.

V-doped titanium mixed oxides as efficient catalysts for oxidation of alcohols and olefins

V/TiO2 nanoparticles were synthesized by a one-pot solution combustion method using ammonium metavanadate and titanyl nitrate as a source of vanadium and titanium, respectively. Atomic absorption spectroscopy (AAS), FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the physicochemical properties of this compound. This compound shows efficient catalytic reactivity for epoxidation of olefins and oxidation of alcohols in the presence of H2O2 as an oxidant.

Preparation of TiN nanopowder by carbothermal reduction of a combustion synthesized precursor

Abstract TiN nanopowder was synthesized by carbothermal reduction method by using a (TiO 2 + C) precursor derived from titanyl nitrate, urea, glucose, ammonium nitrate, and citric acid mixed solution. The results revealed that the obtained precursor consisted of flake particles with a uniform dispersion of amorphous TiO 2 and C. The precursor powders were subsequently calcined under nitrogen at 900–1300 °C for 2 h. The initial transformation of TiO 2 to TiN, by adopting this route, occurred at 900 °C. Moreover, TiO x N y , TiO 2 , and carbon below 1200 °C, and TiC x N y , TiO x N y , TiO 2 , and carbon at (or above 1200 °C) were found to be as impurities with the calcined products. The lattice parameter of TiN synthesized at 1100 °C (α = 4.240 A) agrees well with the theoretical value (α = 4.241 A). TiN powder, synthesized at 1100 °C, exhibited well-distributed spherical particles ranging from 80 to 100 nm. The nitrogen, oxygen, and residual carbon contents of TiN powder synthesized at 1100 °C were found to be 20.37 wt.%, 1.91 wt.%, and 3.36 wt.%, respectively.

Combustion synthesis of graphene oxide–TiO2 hybrid materials for photodegradation of methyl orange

Graphene oxide (GO)–TiO2 hybrid materials with enhanced photocatalytic properties were synthesized by a one-step combustion method using urea and titanyl nitrate as the fuel and oxidizer, respectively. During the synthesis procedure, the precursors containing GO, fuel, and oxidizer were maintained at different combustion temperatures (300–450°C) for 10min to ignite the combustion reaction. The effects of combustion temperatures on the weight loss, chemical status and photocatalytic properties were studied by thermogravimetry and differential scanning calorimetry, X-ray photoelectron spectroscopy, Raman, and photoluminescence. GO in the GO–TiO2 hybrids were not oxidized, but thermally reduced by decomposition of partial oxygen-containing groups. Meantime, the nitrogen doping of GO was achieved. Compared to the neat TiO2 obtained at same condition, GO–TiO2 hybrid obtained at 350°C exhibited enhanced photodegradation performance, which is attributed to the effective photo-generated electron transferring from TiO2 to partially reduced GO, which confirmed by the photoluminescence quenching of TiO2.

A sol–gel combustion synthesis method for TiO2 powders with enhanced photocatalytic activity

TiO2 photocatalytic powders were synthesized by a sol–gel combustion synthesis method in which urea was used as the fuel and titanyl nitrate was used as the oxidizer. Various fuel-to-oxidizer ratios were studied for their effects on the combustion phenomena and the properties of the synthesized TiO2. The fuel-to-oxidizer ratio was found to determine the maximum combustion temperature, which in turn affects the specific surface area, crystallite size, and weight fraction of anatase phase of the synthesized TiO2. The synthesized TiO2 all contain carbonaceous species and are either pure anatase or anatase–rutile mixed phase in crystalline structure. The photocatalytic activity of the TiO2 was found to correlate to a certain degree with the specific surface area, crystallite size, weight fraction of anatase phase, and visible and IR absorbances. The mixed phase TiO2 shows a higher photocatalytic activity than the pure anatase phase TiO2 when containing a small fraction ( ~25 wt%) of rutile phase. The synthesized TiO2 all show higher photocatalytic activity than Degussa P25 TiO2. The enhanced photocatalytic activity was attributed mainly to sensitization by the carbonaceous species and larger amounts of hydroxyl group adsorbed on the TiO2 surface.

A simple chemical co-precipitation/calcination route for the synthesis of simulated synroc-B and synroc-C powders

A simple chemical co-precipitation/calcination route was developed for the synthesis of simulated synroc-B and synroc-C powders using mostly nitrate salts as starting chemicals and 20% ammonia solution as precipitant. In this route, a mixed solution containing Al-nitrate, Ca-nitrate, Ba-nitrate, zirconyl nitrate and titanyl nitrate in the molar proportion required for synroc-B is added to dilute ammonia solution to precipitate these cations in the form of their hydroxides at room temperature by maintaining pH ≈ 10.5 during precipitation. Formation of a major fluorite phase with minor amounts of anatase, rutile and hollandite phases is observed in the powder obtained after calcination in air at 750 °C. Multiphase crystalline synroc-B matrix containing hollandite, perovskite, zirconolite, and rutile phases is obtained after sintering the heat treated powder in the form of pellets at 1230 °C for 4 h in air. Similarly, pure synroc-C phases with 14 and 20% simulated waste loadings were synthesized following the same synthesis protocol. These pre-treated powders with a high surface area of ∼25 m 2 g −1 gave sintered ceramics having density of ∼90% for 14 and 20% waste loadings.

フッ素ドープ酸化スズ透明立体電極を用いた色素増感太陽電池における電子収集の改善

The collection of injected electrons for dye-sensitized solar cells (DSSCs) was improved by two studies of three dimensional fluorine doped SnO2 transparent electrodes (3D FTO). One of the studies conducted here involved making textured glass substrates of silica sphere particles and low resistance FTO films. The other study involved a transparent 3D FTO electrode incorporated into the porous titania layer. In order to suppress back reactions between I3- ions and FTO, the FTO film surfaces in the DSSCs had to be covered with compact titania films prepared by using titanyl nitrate solutions. We confirmed the time constants for the recombination and collection of the injected electrons by using optical modulation techniques. It was found that these 3D configurations contributed to the improvement in the performance of the DSSCs.

Spectroscopic characterisation of weak interactions in acidic titanyl sulfate–iron(ii) sulfate solutions

The titanyl equilibria in strongly acidic solutions related to the hydrometallurgical production of titania have been investigated in the presence of inorganic ions (ClO(4)(-), NO(3)(-), Cl(-), SO(4)(2-), Fe(2+) and Fe(3+)) using spectroscopic (UV-Vis and EPR) methods. UV-Vis experiments showed no interaction or ion pairing effect in the acidic titanyl nitrate and titanyl perchlorate samples indicating that they would be suitable background electrolytes for further thermodynamic measurements. The stoichiometry of the titanyl chloride complex was determined as TiOCl(2)(0) and its stability constant was calculated (log beta(2) = 1.12 +/- 0.03). The interaction between titanyl and sulfate ions was quantified by determining the stoichiometry (1:1) and stability (log beta(1) = 1.64 +/- 0.06) of the titanyl sulfate species. Weak sulfate complexes were also detected with the ferric (log beta(1) = 2.00 +/- 0.10; log beta(2) = 2.49 +/- 0.08) and ferrous (log beta(1) = 1.52 +/- 0.06) ions under strongly acidic conditions. A double sulfato complex FeTiO(SO(4))(3)(2-) with relatively high stability (log beta = 7.13 +/- 0.07) was found in solutions containing titanyl, ferrous and sulfate ions in sulfuric acid medium. In addition, an EPR signal was assigned to the FeTiO(SO(4))(3)(2-) species. This double sulfato complex was found to be the major metal-containing species in the system similar to that used in the leaching process of ilmenite during the industrial production of titania.

Nanocrystalline TiO2 by three different synthetic approaches: A comparison

A comparison of the efficiency of three different synthetic routes viz. sol-gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured TiO2, is reported. In the sol-gel method, nanocrystalline TiO2 is produced when titanium tetraisopropoxide is templated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1:1 solution of ethanol-hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline TiO2 involved mechanical milling of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline TiO2 is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured TiO2 with an average particle size of ∼ 14 nm is produced by the sol-gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline TiO2 with an average particle size of ∼20 nm after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline TiO2 with an average particle size of less than ∼50 nm. The microstructures of nanocrystalline TiO2 produced by the above three methods are analysed.

Aluminum-doped TiO 2 nano-powders for gas sensors

Nano-powders of pure and Al-doped TiO 2 ceramics were synthesized using a citrate–nitrate auto combustion method. Powders were then used to make thick film gas sensors to measure selectivity and sensitivity in CO and O 2 environment. Titanyl nitrate solution was prepared using commercial TiO 2 powder, hydrofluoric acid (HF) and concentrated nitric acid (HNO 3). An optimized ratio of citrate to nitrate was used to produce TiO 2 nanoparticles. Powder X-ray diffraction data showed that synthesized TiO 2 nano-powders, pure as well as Al-doped, had stable anatase phase up to 800 °C. X-ray fluorescence confirmed the Al concentrations in synthesized nano-powders. BET surface area analysis showed a decrease at 5 wt.% Al addition, followed by an increase at 7.5 wt.% in specific average surface area. Particle size analysis showed particles below 100 nm for both pure and doped TiO 2 even after calcination at 800 °C. The resistance of Al-doped TiO 2 samples was found to be lower than that of pure TiO 2 in O 2 and CO environment. Al-doped TiO 2 gas sensors were more selective and sensitive to CO and O 2 at an operating temperature of 600 °C than pure TiO 2 powders.

Optimization of experimental conditions based on Taguchi robust design for the preparation of nano-sized TiO2 particles by solution combustion method

This investigation was aimed at preparing nanocrystalline TiO2 powder by solution combustion method, and searching the optimum preparing conditions by employing Taguchi robust design method. Taguchi robust design method with L18 orthogonal array was implemented to optimize experimental conditions for preparing nano-sized titania particles. Titanium IV n-butoxide was hydrolyzed to obtain titany1 hydroxide [TiO(OH)2], and titanyl nitrate [TiO(NO3)2] was obtained by reaction of TiO(OH)2 with nitric acid. Finally, the aqueous solution containing titanyl nitrate [TiO(NO3)2] and a fuel, glycine, were mixed and combusted to obtain the nano-sized titania. The optimum conditions obtained by this method are as follows (based on 1 mol of TiO2 per batch): concentration of HPC, 0.053 mg cm−3; mole ratio of Ti:H2O:IPA, 1:4:10; hydrolysis time, one hr; the amounts of HNO3 and glycine are 10 ml and 0.5 g, respectively; nitrated temperature, 298 K and nitrated time, 2 h. TiO2 nanocrystalline (∼15 nm) with high BET surface area (350 m2 g−1) and narrow band gap energy (2.7 eV) were thus obtained.

Phase Composition of Nanocrystalline Titania Synthesized under Hydrothermal Conditions from Different Titanyl Compounds

Data are presented on the phase composition and physicochemical properties of nanocrystalline TiO2 powders prepared via hydrothermal treatment of aqueous titanyl sulfate (TiOSO4), titanyl nitrate (TiO(NO3)2), and aqua complex titanyl oxalate acid (H2TiO(C2O4)2) solutions and amorphous titanyl hydroxide (TiO2 · nH2O) gel (synthesized by precipitating H2TiCl6 with an excess of aqueous ammonia) at 423 and 523 K for 10 min to 6 h at solution concentrations from 0.07 to 0.5 M. The synthesized samples were characterized by x-ray diffraction, thermogravimetry, transmission electron microscopy, and nitrogen BET surface area measurements. It is shown that, independent of the precursor, short-term (10 min) hydrothermal treatment leads to the formation of nanocrystalline anatase (crystallite size d = 10–30 nm), a metastable form of titania. Upon an increase in hydrothermal-treatment time to 6 h, the systems studied exhibit different behaviors. Nanocrystalline anatase may persist (titanyl sulfate solutions and amorphous titanyl hydroxide gel) or transform into rutile (d = 50–100 nm), the thermodynamically stable form of TiO2, through recrystallization processes (titanyl nitrate solutions; 0.07 M H2TiO(C2O4)2 solutions, partial conversion at 423 K and full conversion at 523 K; 0.28 M H2TiO(C2O4)2 solutions, full conversion at 423 K). Also possible is the formation of mesoporous anatase (0.28 M H2TiO(C2O4)2 solution, 523 K, 70- to 90-nm aggregates of crystallites, 10- to 20-nm closed pores containing the solution). A model is proposed according to which the formation of mesoporous oxides is possible at comparable rates of anatase nucleation and growth.

Microwave-Induced Combustion Synthesis of Nanocrystalline TiO2–SiO2 Binary Oxide Material

A nanocrystalline titania–silica (1:1 molar ratio) binary oxide material was synthesized by microwave-induced combustion process in a modified domestic microwave oven (operated at 2.45 GHz frequency and 700 W power) in approximately 60 min from in situ synthesized titanyl nitrate and siliconyl nitrate using urea as fuel. For the sake of comparison, two different types of TiO2–SiO2 powders were also synthesized by the sol-gel and the co-precipitation methods. All the synthesized powders were characterized with the help of thermogravimetriy/differential thermal analysis, x-ray diffraction, transmission electron microscopy (TEM), and Brunauer–Emmett–Teller surface area measurements and the results compared. The as-synthesized TiO2–SiO2 powder obtained by the combustion process showed an average crystallite size of 10 nm and the specific surface area of 115 m2g-1. Among the three differently synthesized TiO2-SiO2 powders, only the microwave-induced combustion synthesis yielded crystalline material. TEM in particular confirmed the presence of nano-sized particles in the microwave-induced combustion-synthesized powder. Among the three analogies, microwave synthesis was found to be superior in terms of ease of processing leading to time and power savings.

Synthesis and Structure of Nanocrystalline TiO2 with Lower Band Gap Showing High Photocatalytic Activity

Nanocrystalline TiO2 was synthesized by the solution combustion method using titanyl nitrate and various fuels such as glycine, hexamethylenetetramine, and oxalyldihydrazide. These catalysts are active under visible light, have optical absorption wavelengths below 600 nm, and show superior photocatalytic activity for the degradation of methylene blue and phenol under UV and solar conditions compared to commercial TiO2, Degussa P-25. The higher photocatalytic activity is attributed to the structure of the catalyst. Various studies such as X-ray diffraction, Raman spectroscopy, Brunauer-Emmett-Teller surface area, thermogravimetric-differential thermal analysis, FT-IR spectroscopy, NMR, UV-vis spectroscopy, and surface acidity measurements were conducted. It was concluded that the primary factor for the enhanced activity of combustion-synthesized catalyst is a larger amount of surface hydroxyl groups and a lowered band gap. The lower band gap can be attributed to the carbon inclusion into the TiO2 giving TiO(2-2x)C(x) VO2**.

Chemical synthesis of nanocrystallineBaTiO3 and Ba1−xSrxTi1−yZryO3 [(i) x = 0.03, y = 0 (ii) x = 0, y = 0.03 ] ceramics

Nanocrystalline BaTiO3 powders were prepared via a chemical process. This process involved the addition ofaqueous barium nitrate, titanyl nitrate, triethanolamine (TEA) and sucrose toproduce a homogeneous complex solution. After the complete evaporation ofhomogenous solution, the Ba–Ti–TEA–sucrose complex decomposed and producedblack, fluffy precursor materials. The precursor materials on calcinations to700 °C for 2 h producednanocrystalline BaTiO3 with the corresponding average x-ray and TEM particle size nm. BaTiO3 powdersmodified with SrTiO3 [Ba1−xSrxTi1−yZryO3 (x = 0.03,y = 0)]and BaZrO3 [Ba1−xSrxTi1−yZryO3 (x = 0,y = 0.03)] were also prepared using this route and investigated through x-ray diffraction and energydispersive x-ray analysis.

Chemical synthesis of PZT powder by auto-combustion of citrate-nitrate gel

A simple and convenient method for the synthesis of PZT powder with different compositions near the morphotropic phase boundary is reported. The technique involves auto-combustion of a citrate-nitrate gel resulting from a thermally induced oxidation-reduction reaction forming an ash, which on calcination produces the desired powder. It is possible to use solid titanium dioxide as one of the starting materials instead of strongly hydrolyzable titanyl nitrate without any compromise with the quality of the final product. The method produces fine, homogeneous powders without any compositional fluctuation after calcination of the burnt ash at an appropriate temperature. Powders formed have an average particle size of around 1.1 μm as determined by Sedigraph and around 0.16 μm based on surface area measurements. Fully tetragonal phase is observed up to 52 mol% ZrO 2 whereas fully rhombohedral phase is obtained with a ZrO 2 content of 54 mol% and greater.

Nanocrystalline BaTiO3 from freeze-dried nitrate solutions

An aqueous, all nitrate, solution-based preparation of BaTiO3 is reported here. Rapid freezing of a barium and titanyl nitrate solution, followed by low temperature sublimitation of the solvent, yielded a freeze-dried nitrate precursor which was thermally processed to produce BaTiO3. XRD revealed that 10 min at temperatures ≧600 °C resulted in the formation of phase pure nanocrystalline BaTiO3. TEM revealed that the material was uniform and nanocrystalline (10–15 nm). The high surface to volume ratio inherent in these small particles stabilized the cubic phase of BaTiO3 at room temperature. It was also found that the average particle size of the BaTiO3 produced was highly dependent upon calcination temperature and only slightly dependent upon annealing time. This result suggests a means of selection of particle size of the product through judicious choice of calcination temperature. The experimental details of the freeze-dried precursor preparation, thermal processing of the precursor, product formation, and product morphology are discussed.