Growth Of TiO Research Articles

Effect of Solvent Mixing and Calcination Temperature on the Growth of TiO2 Nanoparticle Prepared via Sol–Gel Method

Effect of Solvent Mixing and Calcination Temperature on the Growth of TiO₂ Nanoparticle Prepared via Sol–Gel Method

Sol–gel synthesis and optical properties of titanium dioxide thin film

The titanium dioxide (TiO2) is synthesized by sol–gel method using titanium-tetra-iso-propoxide (TTIP) as a starting material, and deposited on the pre-cleaned glass substrate using spin coating technique at optimized parameters. Energy dispersive X-ray (EDX) spectroscopy confirms successful TiO2 growth. The optical properties concerning the transmission and absorption spectra show 85% transparency and 3.28 eV wide optical band gap for indirect transition, calculated from absorbance. The exponential behavior of absorption edge is observed and attributed to the localized states electronic transitions, curtailed in the indirect band gap of the thin film. The film reveals decreasing refractive index with increasing wavelength. The photoluminescence (PL) study ascertains that luminescent properties are due to the surface defects.

TiO2 coated ZnO nanorods growth using NCD process and their gas sensing properties

In this study, we demonstrate the growth of TiO2 coated ZnO nanorods by chemical vapor deposition process (CVD) followed by nano-cluster deposition (NCD). The ZnO nanorods are coated uniformly by TiO2 vapors forming porous shell. The surface morphology and structural properties were investigated by using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy and X-ray diffraction (XRD). The grown TiO2 coated ZnO nanorods were used for the fabrication of gas sensor for the detection of H2 gas. The sensing results clearly show the effect of TiO2 thickness on the ZnO nanorods. The sensitivity of 43.3, 72.9, 79.9, 88.9, and 58.49% were obtained for 0, 10, 20, 20, 30 and 35 min respectively at 320 °C for 500 ppm H2 concentration. The effect of thickness on the sensitivity was investigated.

Phase Transition and Microstructure Development of BaTiO<sub>3</sub> by Thermal Development of BaTiO<sub>3</sub> by Thermal Decomposition Method

The thermal decomposition was used to prepare BaTiO3 powders. Using BaCO3 and TiO2 powders as precursors and heat treatment in the temperature range of 600-1000 °C for 6 hr. The final product (BaTiO3) proceeds through a trace amount of Ba2TiO4. The phase transformation was investigated by X-ray diffraction (XRD) as a function of sintering temperature. The results show that the microstructures of BaTiO3 were developed during sintering at different temperature. In additional, the particle growth of BaCO3 and TiO2 are the major factors to affect of the particle growth mechanism.

Titania and nitrogen-doped carbon co-modification: Their synergic effects on the electrochemical performance of LiFePO4

TiO2 and N-doped carbon co-modified LiFePO4 composites (LFP-TiO2-C-N) have been successfully synthesized by using tetrabutyl titanate (TBOT) and dopamine (DPA) as titanium and N-doped carbon sources, respectively. The LiFePO4 modification is performed by dopamine polymerization in the alkaline environment supplied by the TBOT hydrolyzation process. The resulting LFP-TiO2-C-N materials are characterized by EDS, XPS, TG, ICP and HRTEM to confirm the close adhesion of TiO2 nanoparticles and N-doped carbon layers on the LiFePO4 surfaces. The charge–discharge tests demonstrate that the LFP-TiO2-C-N composites deliver a superior initial capacity of 165.3 mAh·g−1 at 0.1 C and high rate performance with discharge capacities of 145 mAh·g−1 at 1 C and 124 mAh·g−1 at 2 C. The LFP-TiO2-C-N composites can retain 99.4% of the initial capacity after 50 cycles at 1 C, revealing a stable cycling stability. Therefore, the synergistic growth of TiO2 and N-doped carbon on the LFP surface could result in the synergic improvement in the electrochemical performance of cathode.

Characterizations of anodic oxide films formed on Ti6Al4V in the silicate electrolyte with sodium polyacrylate as an additive

Anodic oxidation coatings were prepared on Ti6Al4V alloy in Na2SiO3-based electrolyte with sodium polyacrylate (PAAS) as an additive, to develop a route of making thicker films under 200 V. The addition of PAAS as an anion species in the anodic electrolyte increased the conductivity of the solutions, leading to the reduction in breakdown voltage and thus the more vigorous discharging process on the metal surface during anodization. With the addition of PAAS, more and bigger porous and thicker ceramic coatings were obtained as shown by scanning electron microscopy (SEM) and Image-pro Plus software; the addition of PAAS promoted the growth of robust rutile TiO2 and/or Al2TiO5 in the anodic coatings; however, the excessive addition of PAAS resulted in the incorporation of more amorphous silicates in the thicker outer anodic films as shown from the EDS measurement, X-ray diffraction and Raman spectra. Therefore, the microhardness and adhesion of the anodic samples with PAAS at an appropriate concentration of 0.7 g/L improved by about 2 times and 4 times, respectively; their friction coefficient and wearing rate were also reduced to quite lower values compared to those for the anodic sample without PAAS addition.

Interface engineered construction of porous g-C3N4/TiO2 heterostructure for enhanced photocatalysis of organic pollutants

A porous g-C3N4/TiO2 with hierarchical heterostructure has been successfully fabricated through a in situ assembling of small needle-like TiO2 on the surface of ultrathin g-C3N4 sheets. The ultrathin g-C3N4 sheets with carbon vacancies and rich hydroxyl groups were found to facilitate the nucleation and in situ growth of TiO2 and also to modulate the surface chemical activity of the g-C3N4/TiO2 hierarchical heterostructure. The as-designed photocatalytic heterojunction degraded Acid Orange with 82% efficiency after 10 min under simulated solar light, and possessed excellent cycle stability. Relative physical characterizations and photochemical experiments reveal that engineering the interface/surface of g-C3N4 plays a vital role in effectively constructing heterostructures of g-C3N4/TiO2, thus realizing efficient photoinduced electron-hole separation during photocatalytic process.

The first-principle study of oleic acid/hydrazine exciting the growth of TiO 2 (100) crystal face

Surfactants play an important role in controlling the growth of nanostructures. Previous experiments have shown that oleic acid and hydrazine hydrate can control the growth of titanium dioxide (TiO...

Investigation on the Particle Growth of Rutile TiO2 Suppressed by Manganese

In this paper, we present the results of an investigation on the crystallite growth of rutile TiO2 and the formation of Mn–O–Ti bonds in a TiO2/manganese composition. The effects of manganese loading from 20 wt% to 80 wt%, into TiO2 at a temperature of 1200°C on the structural properties, have been studied. The material’sproperties have been characterized on the basis of the experimental data obtained using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). It has been found that an increase of the loading by manganese up to 80 wt% leads to a decrease of the rutile crystallites size and an increase of the amount of Mn–O–Ti bonds. The analysis based on the interpretation of both XRD patterns and FTIR spectrum allows one to explain the reduction of the crystallite size of rutile TiO2 by an increase of the manganese loading.

Highly improved photoelectrocatalytic efficiency and stability of WO3 photoanodes by the facile in situ growth of TiO2 branch overlayers.

The development of highly efficient and stable visible-light-responsive photoanode materials is essential for practical photoelectrocatalytic (PEC) applications. In this work, a novel method was proposed to enhance the PEC efficiency and stability of WO3 photoanodes by the facile in situ growth of TiO2 branch overlayers on WO3 nanoplates (TWNP) based on the lattice match between monoclinic WO3 and anatase TiO2. The WO3 nanoplates (WNP) with a fluted body and a thickness of 160 nm were first prepared on tungsten foil by a hydrothermal method. Then, numerous 001-oriented anatase TiO2 branches were directly grown in situ on the WNP with an average thickness of 50 nm and a length of 35 ± 5 nm. TWNP exhibited a photocurrent of ∼2.37 mA cm-2, which is 157% of that of WNP, and showed no obvious decay over 100 h continuous testing, compared to only 11.8% that remained for WNP. During the PEC degradation of phenol, the rate constant was 0.322 h-1 for TWNP while it was only 0.131 h-1 for WNP, and the activity of TWNP remained at 97.2% after 10 repeat tests compared to only 67.4% for WNP. According to the transient photovoltage and transient photocurrent measurements, these improvements can be attributed to the TiO2 branches which enhanced the charge separation efficiency and surface reaction kinetics, and hindered the inactivation of TWNP by providing an atomic-level protective cover. Overall, the in situ wet chemical growth of the TiO2 branches is a meaningful way to overcome WO3's drawbacks, i.e., sluggish surface reaction kinetics, rapid charge recombination and gradual loss of photoactivity, to improve the PEC activity and stability of WO3 photoanodes.

The Catalyst-Assisted Epitaxial Growth of Ferromagnetic TiO <sub>2</sub>/TiN Nanowires

We report a novel method of growth for single-crystalline TiO2/TiN nanowires through oxidation of epitaxial TiN nanowires on Si/SiO2 (amorphous) and sapphire (crystalline) as practical substrates. We propose that the laser ablated Ti and N diffuse into molten Au to form TiN nano-dots where the growth rate of nanowires is directly proportional to the laser ablation flux due to high diffusion in molten Au. The TiN nanowires were grown by Pulsed Laser Deposition method using Au as a catalyst. The TiN nanowires were then oxidized to create TiO2/TiN core-shell nanowires. The growth of TiO2 (rutile) occurs by domain matching epitaxy paradigm in such a way that (002) planes of the TiO2 match with (200) plane of TiN, where the TiO2 thickness can be tuned by adjustment of oxidation time and temperature. This design provides a core-shell structure of TiO2/TiN integrated with silicon and sapphire substrates. The Rutile TiO2 nanowires show ferromagnetic behavior, while the as-grown TiN exhibits diamagnetic behavior. The SEM, TEM, and EBSD are used to characterize the microstructure and atomic alignments of TiO2 nanowires. The simple method of oxidation along with tunable magnetic properties provides benefits to many smart applications where the magnetic field can be used as an external stimulation.

Microwave-assisted solvothermal: An efficient and new method to obtain hydrophobic wood surfaces

The objective of this work was to form a hydrophobic surface in a highly porous wood by coating and incorporating TiO2 micro/nano structures through the microwave-assisted solvotermal method, without need any pre- or post-modification of the wood substrate, using low temperatures and short times. The behavior and morphology of the TiO2-treated surfaces was characterized using scanning electron microscopy (SEM), while the elemental composition was determined via energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The results indicated that the crystallization of the TiO2 anatase phase was efficient and fully coated the wood surface during the solvothermal process. The treated wood contained TiO2 particles with an average diameter of 200 nm that also allowed to coat an abundant fraction of tracheids cell walls. When investigated through X-ray spectroscopy-mapping, the element titanium appeared abundantly throughout the wood. After TiO2 growth in wood through the microwave-assisted solvotermal method, a roughness at the micro/nano scales structures was created on the wood surface, originating an increase in the contact angle up to 137°, which characterizes the appearance of a hydrophobic surface. The TiO2-treated wood demonstrated 85% of water absorption after 400 hours of immersion, while untreated wood reached 160%, suggesting that the microwave-assisted solvotermal process promotes a delay in the progression of water absorption. This feature can improve the dimensional stability of wood, contributing to the increase of its durability and applications.

Direct Li+ incorporation during the anodic formation of compact TiO2 layers.

In this work, compact titanium oxide layers are formed by anodization in 1 M H3PO4 aqueous electrolyte containing LiClO4. Elastic Recoil Detection Analysis (ERDA) measurements demonstrate that incorporation of lithium ions occurs during anodization, and cell-voltage transient measurements evidence the different electronic properties of Li-doped TiO2 layers. The mechanism of direct incorporation of Li during the fabrication of TiO2 layers is discussed.

Influence of substrate on the structure of predominantly anatase TiO2 films grown by reactive sputtering.

TiO2 films are grown on LaAlO3 (001), Si (100) and SiO2 substrates by reactive radio frequency sputtering. X-ray diffraction (XRD) pole figures revealed important characteristics about the texture and phase distribution on those films. Combined with spectroscopic ellipsometry, the pole figures allowed the analysis of the growth characteristics over the whole volume of the layers. Details in the microstructure of the films were probed using transmission electron spectroscopy. Anatase is the dominating phase in the films grown on all substrates. On TiO2/LaAlO3 fims, the mosaicity is very low, so that the pole figure closely resembles that of anatase monocrystals. Detailed inspection of XRD pole figures reveals a small amount of rutile in the TiO2/LaAlO3 films. For the growth of TiO2 onto SiO2, rutile and brookite phases are also detected. Transmission electron microscopy and XRD results show the formation of anatase {112} twins in films grown on the different substrates, suggesting that the anatase {112} twin mediates the growth of rutile and brookite phases. Optical results are in agreement with the XRD observations: the optical properties of TiO2/LaAlO3 films are similar to the ordinary values of bulk anatase crystals, indicating the orientation of the film in the [001] direction, whereas results for TiO2/SiO2 are compatible with lower crystalline ordering.

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Formation and Particle Growth of TiO2 in Silica Xerogel Glass Ceramic During a Sintering Process

Characterization and Computation of Yb/TiO₂ and Its Photocatalytic Degradation with Benzohydroxamic Acid.

Yb-doped TiO2 (Yb/TiO2) compositions were synthesized by sol-gel method, and the prepared materials were characterized by X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse-reflectance spectrum (UV-Vis DRS), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), energy dispersive spectrometer (EDS), and N2 adsorption. A beneficiation reagent of benzohydroxamic acid (BHA) was used to test the photocatalytic activity of Yb/TiO2. The characterizations indicate that the doping of Yb could inhibit the crystal growth of TiO2, enhance the specific surface area, increase the binding energy of Ti2p, and also slightly expand the adsorption ranges to visible light. Furthermore, the computation of band structure also indicates that Yb-doped TiO2 could make the forbidden band narrower than pure anatase TiO2, which presents a red shift in the absorption spectrum. As a result of the photodegradation experiment on BHA, Yb/TiO2 (0.50% in mass) sintered at 450 °C displayed the highest catalytic activity for BHA when compared with pure TiO2 or other doped Yb/TiO2 compositions, and more than 89.2% of the total organic carbon was removed after 120 min. Almost all anions, including Cl−, HCO3−, NO3−, and SO42−, inhibited the degradation of BHA by Yb/TiO2, and their inhibition effects followed the order of HCO3− > NO3− > SO42− > Cl−. Cations of Na+, K+, Ca2+, and Mg2+ displayed a slight suppressing effect due to the impact of Cl− coexisting in the solution. In addition, Yb/TiO2 maintained a high photocatalytic ability with respect to BHA after four runs. It is hypothesized that ·OH is one of the main species involved in the photodegradation of BHA, and the mutual transformation of Yb3+ and Yb2+ could promote the separation of electron-hole pairs.

Self-powered wire type UV sensor using in-situ radial growth of BaTiO3 and TiO2 nanostructures on human hair sized single Ti-wire

A flexible, non-planar, human hair sized [Diameter (Ø) ≈100 μm, Length (L) ≤6 cm] Ti-wire/BaTiO3 (BTO) core-shell nanostructures (NSs) was developed using chemical oxidation-modification (COM) method followed by a low-temperature hydrothermal technique. COM method of flexible/non-flexible Ti-wires (Ø ≈ 800 μm, 100 μm) outer surface generates uniform distribution/continuous radial growth of TiO2 nanoneedles/nanoparticles having anatase crystalline phase. Photo-responsive performance investigated by fabricating the TiO2 NSs/Ti wire (TW) based UV sensors as a function of fixed bias voltages (±1 V and ±7 V) under various light sources having wavelengths (λ) 365 nm, 405 nm and 535 nm. TW-UV sensor (Ø ≈ 800 μm) has higher photo-responsivity ≈35.024 μA/W than the TW-UV sensor (Ø ≈ 100 μm) under the light intensity ≈18 mW/cm2 (λ ≈ 365 nm) at bias voltage ≈−1 V, respectively. Further, the XPS spectra of the tetragonal crystalline phase of radially grown BTO NSs confirms the presence of Ba 2+ and Ti +4 oxidation states directly connected to the internal stresses of TiO6 octahedron in BTO lattice. Next, flexible wire based piezoelectric nanogenerator (FW-PNG) was fabricated to harness the mechanical energy, biomechanical motions into useful electrical energy. Realized self-powered UV sensor by the parallel connection between FW-PNG and TW-UV sensor as a function of constant mechanical load (2 N) under various light intensities (18, 40 and 60 mW/cm2) of source wavelength 365 nm, respectively. This study can pave the way for developing micro/nanodevices on non-planar mechanical structures; human hair sized energy harvesters and self-powered sensors.

High-fraction brookite films from amorphous precursors

Structure-specific synthesis processes are of key importance to the growth of polymorphic functional compounds such as TiO2, where material properties strongly depend on structure as well as chemistry. The robust growth of the brookite polymorph of TiO2, a promising photocatalyst, has been difficult in both powder and thin-film forms due to the disparity of reported synthesis techniques, their highly specific nature, and lack of mechanistic understanding. In this work, we report the growth of high-fraction (~95%) brookite thin films prepared by annealing amorphous titania precursor films deposited by pulsed laser deposition. We characterize the crystallization process, eliminating the previously suggested roles of substrate templating and Na helper ions in driving brookite formation. Instead, we link phase selection directly to film thickness, offering a novel, generalizable route to brookite growth that does not rely on the presence of extraneous elements or particular lattice-matched substrates. In addition to providing a new synthesis route to brookite thin films, our results take a step towards resolving the problem of phase selection in TiO2 growth, contributing to the further development of this promising functional material.

Nanoscale Manipulation of Spinel Lithium Nickel Manganese Oxide Surface by Multisite Ti Occupation as High-Performance Cathode.

A novel two-step surface modification method that includes atomic layer deposition (ALD) of TiO2 followed by post-annealing treatment on spinel LiNi0.5 Mn1.5 O4 (LNMO) cathode material is developed to optimize the performance. The performance improvement can be attributed to the formation of a TiMn2 O4 (TMO)-like spinel phase resulting from the reaction of TiO2 with the surface LNMO. The Ti incorporation into the tetrahedral sites helps to combat the impedance growth that stems from continuous irreversible structural transition. The TMO-like spinel phase also alleviates the electrolyte decomposition during electrochemical cycling. 25 ALD cycles of TiO2 growth are found to be the optimized parameter toward capacity, Coulombic efficiency, stability, and rate capability enhancement. A detailed understanding of this surface modification mechanism has been demonstrated. This work provides a new insight into the atomic-scale surface structural modification using ALD and post-treatment, which is of great importance for the future design of cathode materials.

Oxidation of Al2O3 Scale-Forming MAX Phases in Turbine Environments

High temperature oxidation of alumina-forming MAX phases, Ti2AlC and Cr2AlC, were examined under turbine engine environments and coating configurations. Thermogravimetric furnace tests of Ti2AlC showed a rapid initial transient due to non-protective TiO2 growth. Subsequent well-behaved cubic kinetics for alumina scale growth were shown from 1273 K to 1673 K (1000 °C to 1400 °C). These possessed an activation energy of 335 kJ/mol, consistent with estimates of grain boundary diffusivity of oxygen (~375 kJ/mol). The durability of Ti2AlC under combustion conditions was demonstrated by high pressure burner rig testing at 1373 K to 1573 K (1100 °C to 1300 °C). Here good stability and cubic kinetics also applied, but produced lower weight gains due to volatile TiO(OH)2 formation in water vapor combustion gas. Excellent thermal stability was also shown for yttria-stabilized zirconia thermal barrier coatings deposited on Ti2AlC substrates in 2500-hour furnace tests at 1373 K to 1573 K (1100 °C to 1300 °C). These sustained a record 35 µm of scale as compared to 7 μm observed at failure for typical superalloy systems. In contrast, scale and TBC spallation became prevalent on Cr2AlC substrates above 1423 K (1150 °C). Cr2AlC diffusion couples with superalloys exhibited good long-term mechanical/oxidative stability at 1073 K (800 °C), as would be needed for corrosion-resistant coatings. However, diffusion zones containing a NiAl-Cr7C3 matrix with MC and M3B2 particulates were commonly formed and became extensive at 1423 K (1150 °C).