Introduction Of TiO2 Research Articles

Reduced leakage current, enhanced ferroelectric and dielectric properties in Mn-doped BiFeO3 thin film composited with TiO2 layers

Abstract The 2 mol% Mn-doped Bi1.05FeO3 (abbreviated as BFOMn, S0), BFOMn composited films with TiO2 layer at the surface of BFOMn (S1), and on the interface between BFOMn film and substrate (S2), as well as at the both sides of the BFOMn film (S3) were prepared on indium tin oxide (ITO)/glass substrates through a chemical solution deposition process. The effects of TiO2 layers deposited at different positions on microstructure, insulating, ferroelectric and dielectric performances are fully investigated. The crystallized perovskite structures without any secondary phases are well maintained in all samples. Increased grain sizes can be achieved with the introduction of TiO2. Among these films, S3 has large average grain size and possesses decreased leakage current density of 7.2 × 10−5 A/cm2 under 400 kV/cm, relatively large remanent polarization (Pr) value of 82.3 μC/cm2 under 3333 kV/cm at 10 kHz, larger dielectric constant (∼ 330) and smaller dissipation factor (∼ 0.04) at 100 kHz. These results demonstrate that introducing TiO2 layers into appropriate positions can be a feasible way to improve the microstructure and enhance the electrical properties of BFO-based films.

Insight into the role of TiO2 modified activated carbon fibers for the enhanced performance in low-temperature NH3-SCR

TiO2-modified activated carbon fiber (ACF) was prepared by a dip-coating method, and supported with CeO2 nanoparticles. The catalysts were applied in the low temperature selective catalytic reduction (SCR) of NO for the first time and exhibited significantly higher NO conversion than the unmodified catalyst in the entire temperature range. Different characterizations were carried out to show that the redox and acidic properties were closely related to the superior catalytic performance. Furthermore, the promotional mechanism was elucidated from the changes in the structure and surface properties of catalysts. It was verified that the introduction of TiO2 not only enhanced the concentration of surface chemisorbed oxygen and surface Ce3+ but also improved the adsorption and activation of NH3 and NO, thus more -NH2 and nitrate species were generated to participate in SCR reaction, which was attributed to a synergistic interaction between TiO2 and CeO2.

Effect of TiO2 on the thermal and optical properties of Er3+/Yb3+ co-doped tellurite glasses for optical sensor

Er3+/Yb3+ co-doped tellurite glasses (83-x)TeO2–10Nb2O5–5Al2O3–xTiO2–1Er2O3–1Yb2O3 where x=0, 2.5, 5, 7.5 and 10 mol% were fabricated by the conventional melt quenching technique. The structural, thermal and optical properties of the tellurite glasses were studied in dependence of the TiO2 concentration. All samples exhibit an amorphous structure which was modified by the introduction of TiO2 according to the X-Ray Diffraction (XRD) and Raman spectroscopy results. Differential scanning calorimetry (DSC) shows that the glass transition temperature and thermal stability increases with the addition of TiO2. The highest value of glass transition temperature (Tg) was 722 K which is one of the highest values found in the literature. On the other hand, the thermometric properties of two representative samples were studied by the fluorescence intensity ratio (FIR) technique. The maximum sensor sensitivity was 4.48 x 10–3 *K–1 at the 490 K temperature for sample with 5 mol% of TiO2 and 5.94 x 10–3 *K–1 at the 480 K temperature for sample with 7.5 mol% of TiO2 corresponding to 32% increase in the maximum sensor sensitivity by increasing TiO2 concentration. These results suggest that the presented host matrix is a good candidate for high temperature sensing applications.

PHB/PCL fibrous membranes modified with SiO2@TiO2-based core@shell composite nanoparticles for hydrophobic and antibacterial applications.

In order to prepare multifunctional fibrous membranes with hydrophobicity, antibacterial properties and UV resistance, we used silica and titanium dioxide for preparing SiO2@TiO2 nanoparticles (SiO2@TiO2 NPs) to create roughness on the fibrous membranes surfaces. The introduction of TiO2 was used for improving UV resistance. N-Halamine precursor and silane precursor were introduced to modify SiO2@TiO2 NPs to synthesize SiO2@TiO2-based core@shell composite nanoparticles. The hydrophobic antibacterial fibrous membranes were prepared by a dip-pad process of electrospun biodegradable polyhydroxybutyrate/poly-ε-caprolactone (PHB/PCL) with the synthesized SiO2@TiO2-based core@shell composite nanoparticles. TEM, SEM and FT-IR were used to characterize the synthesized SiO2@TiO2-based core@shell composite nanoparticles and the hydrophobic antibacterial fibrous membranes. The fibrous membranes not only showed excellent hydrophobicity with an average water contact angle of 144° ± 1°, but also appreciable air permeability. The chlorinated fibrous membranes could inactivate all S. aureus and E. coli O157:H7 after 5 min and 60 min of contact, respectively. In addition, the chlorinated fibrous membranes exhibited outstanding cell compatibility with 102.1% of cell viability. Therefore, the prepared hydrophobic antibacterial degradable fibrous membranes may have great potential application for packaging materials.

In situ TiO2 decorated carbon paper as negative electrode for vanadium redox battery

Developing high-performance electrode is crucial to energy storage performance of vanadium redox battery. Herein, TiO2 decorated carbon paper was developed by hydrothermal route with various treatment time, and employed as negative electrode for vanadium redox battery. TiO2 can be in situ covered on carbon paper by hydrothermal route. Wetting performance of carbon paper is markedly enhanced by introduction of TiO2. Compared with raw carbon paper, TiO2 decorated carbon paper demonstrates excellent electrochemical performance towards V3+/V2+ couple. The sample treated for 6 h (CP-H06) exhibits the best electrochemical properties. The enhanced performance comes from the accelerated transfer of vanadium ions and electrons. The single cell testing indicates that the cell performances are improved significantly by using CP-H06 as negative electrode in terms of increased discharge capacity and energy efficiency. Discharge capacity and energy efficiency increase by 17.8% and 6.4% by using CP-H06 at 100 mA cm−2, respectively. Our study reveals that TiO2 decorated carbon paper with outstanding electrochemical performance exhibits a promising prospect in the energy storage system of vanadium redox battery.

An ultrasensitive electrochemiluminescence biosensor for detection of MicroRNA by in-situ electrochemically generated copper nanoclusters as luminophore and TiO2 as coreaction accelerator

Herein, we constructed an ultrasensitive electrochemiluminescence (ECL) biosensor for detecting microRNA-21 (miR-21) based on in-situ generation of copper nanoclusters (Cu NCs) as luminophore and titanium dioxide (TiO2) as coreaction accelerator. First, numerous AT-rich double-stranded DNA (dsDNA) was produced from the conversion of a small amount of target miR-21 via the combination of exonuclease III (Exo III)-assisted amplification and hybridization chain reaction (HCR), which could reduce the aggregation-caused self-etching effect of Cu NCs and improve the emitting of Cu NCs. Simultaneously, the introduction of TiO2 in the sensing interface not just acted as the immobilizer of dsDNA-stabilized Cu NCs, more than acted as the coreaction accelerator to accelerate the reduction of the coreaction reagent (S2O82−) for significantly enhancing the ECL efficiency of Cu NCs. The biosensor showed an excellent linear relationship in the concentration range from 100 aM to 100 pM with the detection limit of 19.05 aM Impressively, the strategy not only opened up a novel and efficient preparation method for the Cu NCs, but expanded the application of Cu NCs in ultrasensitive biodetection owing to the addition of coreaction accelerator.

Three-dimensional BiOI/TiO2 heterostructures with photocatalytic activity under visible light irradiation

The BiOI/TiO2 heterostructures with microsphere morphology were successfully synthesized via a solvent-thermal method. The photocatalytic performance of BiOI/TiO2 heterostructures was investigated via the degradation of Rhodamine B (RhB). The results indicate that the BiOI/TiO2 heterostructures exhibited excellent photocatalytic performance with a maximum RhB degradation rate of 91% after 2 h of visible light irradiation, and the RhB molecules were mainly degraded by the holes and superoxide radicals. The enhanced photocatalytic performance of the heterostructures was mainly ascribed to its large specific surface areas and the reduced recombination rate of the photo-generated electron–hole pairs, which caused by the introduction of TiO2.

Melting Features and Viscosity of TiO2-Containing Primary Slag in a Blast Furnace

Abstract The performance of the primary slag in the cohesive zone of blast furnace is critical for smooth operation of blast furnace ironmaking process. In the present work, the CaO–SiO2–MgO–TiO2–Al2O3–FeO slag system was studied to identify the influence of the FeO and the TiO2 on the melting features and viscosity. The temperatures of melting features are found to decrease with increasing FeO from 5 wt% to 20 wt% and increase with increasing TiO2 from 5 wt% to 15 wt%. The viscosities of the slag change with TiO2 can be divided into four periods, which are slow period, rapid period, slow down period and dramatically rise period. The introduction of TiO2 into silicate network performs as network modifier at high temperature and network former at a relative low temperature. FeO can decrease the effect of Ti2O6 4– chain units and decrease the precipitation temperature of the solid phase.

Investigation on the electrical properties of palm oil and coconut oil based TiO2 nanofluids

This paper presents an examination on the electrical properties of Palm Oil (PO) and Coconut Oil (CO) under the presence of semi-conductive nanoparticle, Titanium (IV) Oxide (TiO 2 ). The type of PO used in this study was Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein. TiO2 was dispersed into RBDPO and CO at volume concentrations ranging from 0.001% to 0.05%. The effect of surfactant, Cetrimonium Bromide (CTAB) was also examined and the morphology of RBDPO and CO based TiO 2 nanofluid was observed through Transmission Electron Microscope (TEM). A number of measurements were carried out including the AC/lightning breakdown voltages, dielectric dissipation factor, relative permittivity and resistivity. Statistical analysis was carried out through Weibull distribution to determine the AC and lightning withstand voltages at 1% probability for RBDPO and CO. It is found that without CTAB, there are only slight improvements on the AC breakdown voltages of the RBDPO and CO with introduction of TiO2 but could decrease with presence of CTAB. The same pattern is found for lightning breakdown voltages of RBDPO and CO under non-uniform field where the highest percentages of increments decrease with introduction of CTAB while the effect is not apparent under quasi-uniform field. Significant effect of CTAB is found on the dielectric dissipation factors and resistivity of RBDPO and CO based TiO 2 nanofluid while the relative permittivity are not affected. The statistical analyses reveal that RBDPO and CO experience apparent increments of the AC breakdown voltages at 1% probability after the introduction of TiO 2 regardless with or without CTAB. The improvements done by TiO2 on the lightning breakdown voltages at 1% probability for all samples with CTAB under quasi-uniform field are more apparent than non-uniform field.

Effect of talc and titania on the microstructure and mechanical properties of alumina ceramics

AbstractAlumina (Al2O3) ceramics were prepared with nucleating agent of titania (TiO2) and fluxing agent of talc by the normal pressure sintering method. The effects of TiO2 and talc on phase composition, microstructure, and mechanical properties of Al2O3 ceramics, as well the strengthening and toughening mechanism were investigated. It was found that the introduction of TiO2 could be favorable for mullite formation and the improved densification of ceramics, resulting in improved mechanical properties of ceramics as well. Ceramics possess the best comprehensive mechanical performance with fracture toughness of 3.69 MPa·m1/2 and flexural strength of 255.9 MPa when 4 wt.% TiO2 and 15 wt.% talc were added. Mineral bridges and nanocrystallites were found in the glass‐ceramics, which caused the deflection of cracks so that it strengthened the grain boundary and improved the mechanical properties of ceramics.

Preparation of a p-n heterojunction BiFeO3@TiO2 photocatalyst with a core–shell structure for visible-light photocatalytic degradation

Magnetically separable bismuth ferrite (BiFeO3) nanoparticles were fabricated by a citrate self-combustion method and coated with titanium dioxide (TiO2) by hydrolysis of titanium butoxide (Ti(OBu)4) to form BiFeO3@TiO2 core–shell nanocomposites with different mass ratios of TiO2 to BiFeO3. The photocatalytic performance of the catalysts was comprehensively investigated via photocatalytic oxidation of methyl violet (MV) under both ultraviolet and visible-light irradiation. The BiFeO3@TiO2 samples exhibited better photocatalytic performance than either BiFeO3 or TiO2 alone, and a BiFeO3@TiO2 sample with a mass ratio of 1:1 and TiO2 shell thickness of 50–100 nm showed the highest photo-oxidation activity of the catalysts. The enhanced photocatalytic activity was ascribed to the formation of a p-n junction of BiFeO3 and TiO2 with high charge separation efficiency as well as strong light absorption ability. Photoelectrochemical Mott–Schottky (MS) measurements revealed that both the charge carrier transportation and donor density of BiFeO3 were markedly enhanced after introduction of TiO2. The mechanism of MV degradation is mainly attributed to hydroxyl radicals and photogenerated electrons based on energy band theory and the formation of an internal electrostatic field. In addition, the unique core–shell structure of BiFeO3@TiO2 also promotes charge transfer at the BiFeO3/TiO2 interface by increasing the contact area between BiFeO3 and TiO2. Finally, the photocatalytic activity of BiFeO3@TiO2 was further confirmed by degradation of other industrial dyes under visible-light irradiation.

Effect of TiO2 on the viscosity and structure of low-fluoride slag used for electroslag remelting of Ti-containing steels

The viscosity of CaF2–CaO–Al2O3–MgO–(TiO2) slag was measured using a rotating crucible viscometer. Raman spectroscopy analysis was performed to correlate the viscosity to slag structure. The viscosity of the slag was found to decrease with increasing TiO2 content in the slag from 0 to 9.73wt%. The activation energy decreased from 95.16 kJ/mol to 79.40 kJ/mol with increasing TiO2 content in the slag. The introduction of TiO2 into the slag played a destructive role in Al–O–Al structural units and Q4 units by forming simpler structural units of Q2 and Ti2O6 4− chain. The amount of Al–O–Al significantly decreased with increasing TiO2 content. The relative fraction of Q4 units in the [AlO4]5−-tetrahedral units shows a decreasing trend, whereas the relative fraction of Q2 units and Ti2O6 4− chain increases with increasing TiO2 content accordingly. Consequently, the polymerization degree of the slag decreases with increasing TiO2 content. The variation in slag structure is consistent with the change in measured viscosity.

NO reduction by CO over TiO2-Γ-Al2O3 supported In/Ag catalyst under lean burn conditions

TiO2/Γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method, and investigated for NO reduction with CO as the reducing agent under lean burn conditions. The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, H2 temperature-programmed reduction and Fourier transform infrared spectroscopy. TiO2/Γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2. It displayed high dispersion, large amounts of surface active components and high NO adsorption capacity, which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions. The silver species stabilized and improved the dispersion of the indium species. The introduction of TiO2 into the Γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.

Electrospun dual phase Li4Ti5O12-TiO2/C nanocomposites as anodes for high-rate lithium-ion batteries

ABSTRACTDual phase Li4Ti5O12-TiO2/C nanocomposites have been one-step synthesized by the method of electrospinning. When the Li4Ti5O12-TiO2/C nanocomposites are used as anode material for lithium-ion batteries, it exhibits excellent capacity of 186.5 mAh/g at 4000 mA/g with a good cycling performance. Simultaneously, it owns remarkable rate capability and reversible capability. The introduction of TiO2 enhances both the electric conductivity and the lithium ion diffusivity in Li4Ti5O12. And then it has good electrochemical performance.

Investigation on phase evolution of the ZnO-B2O3-SiO2 glass ceramics

ZnO-B2O3-SiO2-Al2O3-Na2O glass doped with nucleating agent TiO2 was prepared with melting-quenching method and the effect of nucleating agent on the crystallization behavior and phase evolution of this glass was investigated by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The experimental results show that the glass transition temperature and the first crystallization temperature decrease from 630 °C and 765 °C to 595 °C and 740 °C, respectively, with introduction of TiO2 into glass. There is no diffraction peaks in the XRD pattern but it is no longer transparent for the base glass without nucleating agent after heat treatment, which suggests the serious phase separation occurred, and the observation by SEM indicates that the phase separation is developed by nucleation and growth mechanism. However, there are two different crystals ZnAl2O4 and NaAlSiO4 present in the glass containing TiO2 after heat treating at 575 °C for 2 h and 740 °C for 6 h, respectively. What is interesting is that NaAlSiO4 disappears as the crystallization time at 740 °C increases from 6 h to 12 h, and more ZnAl2O4 crystal is formed, namely, the further formation of ZnAl2O4 is at cost of NaAlSiO4 with increasing crystallization time. And observation of the morphology of glass ceramics shows great difference with increasing crystallization time. Moreover, the ability of ZnO-B2O3-SiO2-Al2O3-Na2O glass ceramics against attacking of 1M HCl solution is increased by the crystals precipitated in heat treatment process.

Effect of TiO2 nanoparticles on the viscoelastic and time-dependent behaviors of TiO2/epoxy particulate nanocomposite

Abstract In this work, the effects of nano titania are investigated on mechanical, creep, and viscoelastic behaviors of epoxy resin. For this purpose, 0.25, 0.5, and 1 vol.% of TiO2 nanoparticles were mixed with thermoset epoxy resin by mechanical and ultrasonic homogenizers and then the tensile, creep, and DMTA test samples were fabricated. The results of tensile tests show that the addition of TiO2 nanopowder slightly increased the strength and Young’s modulus of epoxy resin. However, the ultimate tensile strain or the rupture strain of nanocomposites is decreased. In addition, to understand the viscoelastic behavior of nanocomposites, the DMTA and tensile creep tests have been done. Tensile creep test has been done by DMTA and universal test machine. Both results confirmed that the creep resistance of nanocomposites has extensively improved by adding the titania nanoparticles. Variations of storage modulus, loss modulus, and tan (δ) by adding TiO2 nanopowder were examined in two modes of bending and tension. Storage and loss moduli of nanocomposite are considerably increased in all the states, but the storage modulus was more sensitive to TiO2 loading intensity. Thus, test results showed that introduction of TiO2 in the epoxy resin leads to the improvement of mechanical, creep resistance, and viscoelastic properties of nanocomposites. Due to the wide applications of epoxy resins in engineering devices, this method of reinforcement can be practical and useful to overcome some limitations of epoxy resins.

Effect of TiO2 on the optical, structural and crystallization behavior of barium borate glasses

Collective characterizations of prepared binary barium borate glass (50 mol % BaO – 50 mol % B2O3) together with samples containing increasing added TiO2 contents (5% → 30%) were carried out by optical and FT infrared absorption measurements. FT infrared and X-ray diffraction analysis were done for heat treated glass – ceramic derivatives prepared through two step regime process. Optical spectra of the glasses reveal the presence of titanium ions mainly in the tetravalent state imparting additional UV band beside strong UV absorption due to trace iron impurity. IR spectral studies indicate the presence of triangular and tetrahedral borate groups through the modification of BaO to some BO3 to BO4 groups beside the presence of titanium ions as interfering or overlapping TiO4 or BOTi groupings in the glassy network. Crystalline X-ray diffraction results indicate the separation of crystalline barium borate of the composition (2BaO.5 B2O3) as a main constituent together with some crystalline alkali titanates confirming the role of TiO2 of both as nucleating agent beside acting as structural forming through reaction with alkali oxides to form crystalline titanates. The optical band gap values reveal progressive decrease and increase of Urbach energy with TiO2 content and the same for the refractive index values and all these parameters are correlated with the proposed changes in the glass constitution with the introduction of TiO2. The additional thermal expansion measurements indicate the peculiar characteristic negative expansion up to 300 °C and after which an increase in the coefficient of thermal expansion is identified with the increase in temperature. The thermal parameters are also correlated with the modification of the glass structure by the introduction of titanium ions.

Synergetic effect of TiO2 as co-catalyst for enhanced visible light photocatalytic reduction of Cr(VI) on MoSe2

MoSe2-TiO2 composites were successfully synthesized via a facile solvothermal method. Their morphology, structure and photocatalytic activity in the reduction of Cr(VI) were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectra, respectively. The results show that the introduction of TiO2 into MoSe2 boosts the light harvesting efficiency and charge separation and transfer due to their synergistic effect, thus enhancing the visible light photocatalytic activity of MoSe2 with a maximum Cr(VI) reduction rate of 91% at 120min compared with pure MoSe2 (61%) and TiO2 (5%).

Charge transfer process at the Ag/MPH/TiO2 interface by SERS: alignment of the Fermi level.

A nanoscale metal-molecule-semiconductor assembly (Ag/4-mercaptophenol/TiO2) has been fabricated over Au nanoparticle (NP) films as a model to study the interfacial charge transfer (CT) effects involved in Ag/MPH/TiO2. Due to the interaction between Au NPs and Ag NPs, some distinct differences occur in the SERS spectra. We also measured the SERS of Ag/MPH (4-mercaptophenol), Ag/MPH/TiO2, and Au/Ag/MPH/TiO2 assemblies at excitation wavelengths of 477, 514, 532, 633, and 785 nm. We found that the changes in the CT process, caused by the introduction of TiO2 and Au, can be reflected in SERS. Then in combination with other detection methods, we proposed a possible CT process involved in the Ag/MPH, Ag/MPH/TiO2, and Au/Ag/MPH/TiO2 assemblies. A Pt/Ag/MPH/TiO2 assembly was also constructed to verify our proposed CT mechanism. This work not only provides more details about CT between metal-molecule-semiconductor interfaces but also aids in constructing nanoscale models to study interfacial problems with the SERS technique.

Novel Bi2MoO6/TiO2 heterostructure microspheres for degradation of benzene series compound under visible light irradiation

Novel Bi2MoO6/TiO2 heterostructure microspheres were successfully synthesized via a facile solvothermal method. Their morphology, structure and photocatalytic performance in the degradation of phenol and nitrobenzene were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical impedance spectra, UV–vis absorption spectroscopy and total organic carbon analyser, respectively. The results show that the Bi2MoO6/TiO2 heterostructures exhibit excellent photocatalytic performance with maximum phenol and nitrobenzene degradation rates of 96% and 94% and corresponding mineralization rates of 66% and 61% in 300min under visible light irradiation, respectively. The improved photocatalytic performance is mainly ascribed to the reduced electron–hole pair recombination with the introduction of TiO2.