Mixture Of TiO2 Research Articles

Production of calcium and magnesium titanates using concentrated solar energy

Solar energy is an adequate technology for different processes in metallurgy, materials processing, recycling, or ceramic-refractory materials, because of the high temperatures attained which are reached when the solar radiation is concentrated. This growing interest has also emerged from the obtaining of such temperatures without releasing pollutants such as carbon dioxide, SOx, NOx, or dioxins. Other benefits associated with concentrated solar energy are that this energy source is virtually free and the possibility of operating in places isolated from the electrical grid. Therefore, this research proposes the integration of concentrated solar energy in the production of calcium and magnesium titanates, which are materials with increasing demand in the field of electric components. Experimental work was carried out in the Odeillo solar furnace located in Font-Romeu-Odeillo-Via (France) using a 1.5-meter parabolic concentrator and mixtures of CaO and TiO2 and MgO and TiO2 in 1:1 molar ratio. Mixtures were subjected to values of incident radiation exceeding 900 W/m2 without using any special atmosphere and in very short times, which did not surpass 10 min. X-ray diffraction technique was employed to confirm the formation of the CaTiO3 and MgTiO3 perovskites. Therefore, concentrated solar energy might be a novel, fast, and environmentally sustainable manner of producing calcium and magnesium titanates.

Protection behavior of Ti-SiO2 modified potassium silicate coating on K447a alloy at 1000 °C

Potassium silicate coatings cured by calcium hydrogen phosphate and modified by fillers of Ti and SiO2 powders were prepared on K447A alloy at 120 °C. The influences of Ti, SiO2 and both powders on the oxidation behavior of the coated specimens were investigated at 1000 °C for 100 h in static air by thermogravimetry, SEM, XRD and EPMA. The bare K447A alloy suffered severe oxidation at 1000 °C, and the TGO was found to be composited of an outer layer of mixtures of NiCr2O4, CoAl2O4 and rutile TiO2, and an inner α-Al2O3 layer. The potassium silicate coating without filler showed local damages where formation and rapid rupture of bubbles occurred and consequently the local substrate was oxidized. The SiO2 powder in the coatings is more capable of reducing O diffusion thru the coatings than the Ti powder, while the latter is more effective in getting rid of bubble rupture than the former. Thus, the coating modified by 10 wt% Ti and 20 wt% SiO2 showed the best protective performance.

Investigation into the Fuel Characteristics of Biodiesel Synthesized through the Transesterification of Palm Oil Using a TiO2/CH3ONa Nanocatalyst

Biodiesel is a renewable and sustainable alternative fuel to petrol-derived diesel. Decreasing the operating costs by improving the catalyst’s characteristics is an effective way to increase the competitiveness of biodiesel in the fuel market. An aqueous solution of sodium methoxide (CH3ONa), which is a traditional alkaline catalyst, was immersed in nanometer-sized particles of titanium dioxide (TiO2) powder to prepare the strong alkaline catalyst TiO2/CH3ONa. The immersion method was used to enhance the transesterification reaction. The mixture of TiO2 and CH3ONa was calcined in a high-temperature furnace in a range between 150 and 450 °C continuously for 4 h. The heterogeneous alkaline catalyst TiO2/CH3ONa was then used to catalyze the strong alkaline transesterification reaction of palm oil with methanol. The highest content of fatty acid methyl esters (FAMEs), which amounted to 95.9%, was produced when the molar ratio of methanol to palm oil was equal to 6, and 3 wt.% TiO2/CH3ONa was used, based on the weight of the palm oil. The FAMEs produced from the above conditions were also found to have the lowest kinematic viscosity of 4.17 mm2/s, an acid value of 0.32 mg KOH/g oil, and a water content of 0.031 wt.%, as well as the highest heating value of 40.02 MJ/kg and cetane index of 50.05. The lower catalyst amount of 1 wt.%, in contrast, resulted in the lowest cetane index of 49.31. The highest distillation temperature of 355 °C was found when 3 wt.% of the catalyst was added to the reactant mixture with a methanol/palm oil molar ratio of 6. The prepared catalyst is considered effective for improving the fuel characteristics of biodiesel.

Development of Hydrophilic Self-Cleaning and Ultraviolet-Shielding Coatings Incorporating Micro-Titanium Dioxide/Nano-Calcium Carbonate (µ-TiO<sub>2</sub>)/(Nano-CaCO<sub>3</sub>)

The dust accumulation and dirt particles always degrade the transparency of glass, later hampers its various applications such as photovoltaic panels, building glass, and car-windshield. In this study, the hydrophilic self-cleaning coatings have been developed by using the nanocalcium Carbonate particles (nanoCaCO3) and hydrophilic micro-titanium dioxide particles (µ-TiO2). The presence of oxide groups, CO-3 and TiO2- forms a strong attraction of glass to polar water molecules. At the weight ratio of 1: 1 in the CaCO3 to TiO2 mixture, it forms a great hydrophilic property in which the water contact angle (WCA) of coated glass has been recorded as low as 11.46 ±0.85°. The coated glass also showed high transparency in UV and Visible regions. The optical transmission of coated glass was above 89% at the wavelength of 300-400nm and above 97% at the wavelength of 400-800nm. Due to its hydrophilic property, the coated glass is capable of removing the dust particles away via the water stream. The hydrophilic coating spontaneously forms the water-thin film after contact with coated glass without the presence of UV light.

MXene-Derived Oxide Nanoheterostructures for Photocatalytic Sulfamethoxazole Degradation.

Herein, we report for the first time the use of ternary oxide nanoheterostructure photocatalysts derived from (Nb y , Ti1-y )2CT x MXene in the treatment of water. Three different compositions of binary MXenes, viz., (Ti0.75Nb0.25)2CT x , (Ti0.5Nb0.5)2CT x , and (Ti0.25Nb0.75)2CT x (with T x = OH, F, and Cl), were used as single-source precursor to produce TiNbO x -3:1, TiNbO x -1:1, and TiNbO x -1:3 by controlled-atmosphere thermal oxidation. Phase identification and Le Bail refinements confirmed the presence of a mixture of rutile TiO2 and monoclinic Ti2Nb10O29. Morphological investigations through scanning and transmission electron microscopies revealed the retention of layered nanostructures from the MXene precursors and the fusion of TiO2 and Ti2Nb10O29 nanoparticles in forming nanosheets. Among the three oxide nanoheterostructures, TiNbO x -3:1 exhibited the best photocatalytic performance by the removal of 83% of sulfamethoxazole (SMX) after 2 h of reaction. Such a result is explained by a complex influence of structural, morphological, and electronic properties since TiNbO x -3:1 consisted of small-sized crystallites (40-70 nm) and possessed a higher surface area. The suggested electronic band structure is a type-II heterojunction, where the recombination of electrons and holes is minimized during photocatalytic reactions. The photocatalytic degradation of SMX was promoted by the attack of •OH, as evidenced by the detection of 2.2 μM •OH, using coumarin as a probe. This study highlights the potential application of MXene-derived oxide nanoheterostructures in wastewater treatment.

Evaluation of Dye Loading on Photoanodes of Dye-Sensitized Solar Cells Utilizing a Mixture of TiO2 and Magnesium/Aluminum Layered Double Hydroxide (LDH)

Evaluation of Dye Loading on Photoanodes of Dye-Sensitized Solar Cells Utilizing a Mixture of TiO2 and Magnesium/Aluminum Layered Double Hydroxide (LDH)

Advanced design of sol-gel derived multilayered cerium titanate films: structural, surface, photoelectrochemical and photocatalytic properties

Crystallization of Ce2Ti2O7 in the mixture of TiO2 and CeO2 was achieved by the three-layered coating of cerium − titanium mixed sol of the 1 : 1 metals molar ratio on a glass substrate at certain temperature regime in air as proven by XRD, SAED and Raman spectroscopy. Anatase and Ce2Ti2O7 crystallization with XRD undetectable crystallites brought to the increase of the specific surface area of the films. The formation of Ti–O–Ce bonds on the surface of the films was proven by the noticeable shift of Ti2p and O1s XPS maxima compared to TiO2 ones. The additional peaks in Ti2p, O1s and Ce3d XPS spectra belonging to the common bonds between the metals ions were identified for the first time. The bandgap energy and band-edge positions of Ce2Ti2O7 were firstly determined by photoelectrochemical measurements. The inactivity of the films in photocatalytic reductive and oxidative processes was caused by the unfavorable position of the valence band of Ce2Ti2O7 causing the recombination of the photo-formed electron−hole pair.

Corrosion Properties and Passive Film Interface of Inconel 718 in NaNO3 Solution for Laser-Assisted Electrochemical Machining.

Laser-assisted electrochemical machining (ECM) is an ideal manufacturing method for Inconel 718 (IN718) because of the method's high efficiency and good surface quality, and the basis for and key to laser-assisted ECM is its anodic electrochemical dissolution behavior. In this study, IN718 in a 10 wt % NaNO3 solution was subjected to innovative electrochemical testing and laser-assisted ECM experiments to investigate its corrosion properties and the passive film characteristics formed on its surface. The passivation-related behaviors and structures of the passive film were investigated based on open-circuit potentials, dynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy. It was found that there was obvious active-passive-transpassive transition behavior, and the structure of the passive film in laser-assisted ECM exhibited pores and defects, resulting in weak corrosion resistance, compared with IN718 under ECM without laser irradiation. The chemical composition of the passive film was obtained by X-ray photoelectron spectroscopy. The results showed that the passive film was composed mainly of a mixture of NiO, Ni(OH)2, Cr2O3, CrO3, Fe2O3, α-Fe2O3, α-FeOOH, Nb2O5, NbO, MoO3, MoO2, and TiO2. The passive film formed by laser-assisted ECM was rich in NiO and TiO2 and lacked Cr2O3 and MoO3, which validated its pores and defect structures. A corresponding schematic model was also proposed to characterize the interface structure between the IN718 substrate and the passive film. Laser-assisted ECM tests were performed under different current densities and machining times, and the corrosion morphology of IN718 was identified. Corrosion pits and a loose product layer appeared on the machined surface at low current densities, and the dissolution mechanism was pitting. The quantity and depth of the corrosion pits dispersed on the machined surface clearly decreased as the current density increased. Finally, a quantitative corrosion model was established to characterize the dissolution behavior of IN718 in NaNO3 solution during laser-assisted ECM.

Stability Scrutinization of Time Depending Flow of a Ternary Hybrid Nanofluid Past a Shrinking Sheet with Wall Mass Suction Effect

The dynamics of unsteady flow of a ternary hybrid nanofluid on a stretching/shrinking sheet with wall mass suction is numerically analysed. In this study, a mixture of Al2O3, Cu, and TiO2 is employed as additives in water, which serves as the base fluid. The equations governed the problem are simplified into a collection of ODEs by adopting the similarity transformation. Maintaining the flow on a shrinking sheet is reliant on the essential aspect of suction. Furthermore, augmenting the strength of suction amplifies the thermal conductivity process of the flow. Additionally, this study unveils dual solutions existing within a defined range of parameters. It has been determined that one solution exhibits long-term stability, whereas the other solution is deemed unstable through the stability analysis conducted.

Exploring microstructures of metal-doped oxides via simulated Raman spectrum

Solid solution of metal-doped oxide has been widely used in material industry and catalysis process. Its performance is highly correlated with the distribution of doped ions. Due to the complex distribution of doped ions in solid solution and its variation with temperatures, to obtain the microstructures of metal-doped ions in solid solution remains a substantial challenge. Taken Ce1-xZrxO2 as a model, the global structure searching, structures proportion with temperature determined by Boltzmann distribution, and the weighted simulation Raman spectra were integrated to explore the microstructures of metal-doped solid solution oxides. It was further verified by application into rutile and anatase TiO2 mixture, indicating that the present method is feasible to deduce the microstructure of metal composite oxides. We anticipate that it provides a powerful solution to explore microstructures of solid solution and complex metal oxides.

Tribological properties and solid particle erosion wear behavior of Al2O3-13 wt%TiO2/Al2O3-PF composite coatings prepared on resin matrix by supersonic plasma spraying

Resin materials feature exceptional physical properties and inexpensive cost, but unfavorable surface characteristics, such as low wear resistance and poor erosion wear performance, render them tough to satisfy greater demands. The potential option is to prepare supersonic plasma sprayed Al2O3-13 wt%TiO2/Al2O3-phenolic resin (AT13/Al2O3-PF) coating on the surface of the resin matrix. AT13 feedstocks are classified into two types: Al2O3-13 wt%TiO2 powder prepared by the agglomeration granulation process (AT13-1) and the mixture of spherical Al2O3 and TiO2 (approximately 13 wt%) powder (AT13-2). The effect of component dispersion on mechanical and tribological characteristics of coatings was thoroughly investigated, as well as the solid particle erosion wear behavior of coatings. The results illustrated that the evenly dispersed TiO2 phase in AT13-1 coating was prone to homogenize the coating structure, resulting in better tribological characteristics than AT13-2 coating, although erosion wear performance was inferior to AT13-2 coating. The wear rate of AT13-1 coating was 1.36 × 10−5 mm3 (N m)−1, which was 1/21 times that of AT13-2 coating. At the 60° erosion angle, the high porosity of AT13-1 coating resulted in hard phase cracking or hard phase debonding. The high microhardness of AT13-2 coating reduced erosion wear at the 90° erosion angle.

Optical properties of germania and titania at 1064 nm and at 1550 nm

One of the main noise sources in current gravitational-wave detectors is the thermal noise of the high-reflectivity coatings on the main interferometer optics. Coating thermal noise is dominated by the mechanical loss of the high-refractive index material within the coating stacks, Ta2O5 mixed with TiO2 . For upgrades to room-temperature detectors, a mixture of GeO2 and TiO2 is an interesting alternative candidate coating material. While the rather low refractive index of GeO2 increases with increasing TiO2 content, a higher TiO2 content results in a lower threshold temperature before heat treatment leads to crystallisation, and potentially to a degradation of optical properties. For future cryogenic detectors, on the other hand, a higher TiO2 content is beneficial as the TiO2 suppresses the low-temperature mechanical loss peak of GeO2. In this paper, we present the optical properties of coatings—produced by plasma-assisted ion-beam evaporation—with high TiO2 content at 1550 nm, a laser wavelength considered for cryogenic gravitational-wave detectors, as a function of heat-treatment temperature. For comparison, the absorption of pure GeO2 was also measured. Furthermore, results at the currently-used wavelength of 1064 nm are presented.

Structural and optical properties of highly Ag-doped TiO2 thin films prepared by flash thermal evaporation

The present study investigates the structural and optical properties of silver (Ag)-doped titanium dioxide (TiO2) thin films prepared via flash thermal evaporation using TiO2 and Ag powders mixture at various mass ratios. The crystallinity and surface morphology of the films were studied by varying the percentage of Ag content. Structural properties were characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), while optical properties were assessed through optical transmission spectra analysis. Results indicate that Ag doping enhances crystallinity, as evidenced by XRD and Raman spectroscopy, and induces surface plasmon resonance (SPR) absorption attributed to Ag nanoparticles. SEM micrographs reveal agglomerated silver particles on the film surface, confirming Ag diffusion during annealing. Surface analysis through Secondary Ion Mass Spectrometry (SIMS) measurements illustrated the diffusion of Ag within the TiO2 samples and its subsequent accumulation at the surface. We have suggested that the crystallization observed in the evaporated TiO2-Ag thin films may primarily result from the thermal diffusion of Ag metal rather than the annealing process alone. Optical transmission spectra demonstrate a shift in the absorption edge towards the visible region with increasing Ag concentration, indicating enhanced light absorption properties.

Shaping of thermal protective properties of basalt fabric-based composites by direct surface modification using magnetron sputtering technique

Abstract A direct modification of the surface of the basalt fabric was carried out by using magnetron sputtering to obtain composites intended for effective protection against contact and radiant heat. One-layer composite with a coating of aluminum (Al) and zirconium dioxide (ZrO2), two-layer composite with a coating of Al/ZrO2, and two-layer composite with a coating of Al/(ZrO2 + titanium dioxide [TiO2]) were deposited on the fabric surface. Scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis was used to assess the coating on basalt fabrics and determine their chemical composition. Parameters such as thermal conductivity coefficient, resistance to radiant heat, and resistance to contact heat for a contact temperature of 250°C were determined for assessment of the composites from the point of view of protective properties. The similarity analysis of composites was performed to state the impact of coating components’ content and coating thickness on chosen parameters. It was found that a two-layer composite in which the outer layer is Al and the inner layer is a mixture of ZrO2 and TiO2 provides good thermal insulation properties. The composites capable of protecting against contact heat at the first efficiency level and against radiant heat at the second efficiency level were obtained.

Study of the Structural and Optical Properties of the TiO2:Au Nanocomposite Mixture Prepared by Laser Ablation Method

In this study, TiO2, Au, and a mixture of TiO2: Au nanoparticles (NPs) were produced using a Nd: YAG pulsed laser. X-Ray diffraction (XRD), Transmission electron microscopy, and Ultraviolet–visible spectroscopy (UV) was used to characterize the produced nanoparticles. The XRD patterns of TiO2 NP showed that the diffraction peaks values were corresponded to the ICDD card number (21-1272) for the anatase form of TiO2 NPs. The XRD patterns of Au NPs values were corresponded to the ICDD card number (00-004-0784) of Au NPs. The XRD patterns the mixture TiO2: Au nanoparticle with mixing ratios (4:1, 3:2 and 2.5:2.5), it was found that the diffraction peaks were (2θ~ 38.138° and 64.687°) of TiO2 nano-particles, and the diffraction peaks were (2θ~ 44.341° and 77.577° ) Au NPs. The average crystalline size of the prepared nanoparticles was determined by Scherer's technique, it was found that the average crystalline size (TiO2 NPs) is (23.36 nm), whereas mixing titanium oxide with gold nanoparticles (TiO2: Au) increased the average crystallite size to (34.18, 34.15, and 34.20 nm) for the mixing ratios (4:1, 3:2, and 2.5:2.5), respectively. The TEM images showed that the TiO2 NPs are light grey in the combination of (TiO2: Au) NPs, while for the ratio (4-1), the Au NPs are dark, spherical spheres. However, when the ratio of Au particles is increased to (2:3), the TiO2 particles remain light grey but are smaller in size. The absorption spectra of pure TiO2 NPs is in the UV spectrum, whereas the absorption spectrum of the (TiO2: Au) mixture shifts towards the wavelengths of visible light in the range (520-540 nm), according to the optical characteristics of TiO2 NPs and a mixture of (TiO2:Au) NPs. The optical energy gap of pure TiO2 NPs is 3.22eV, and it decreases as the proportion of gold nanoparticles in the mixture increases.

Engineering the heterojunction between TiO2 and In2O3 for improving the solar-driven hydrogen production

Nanostructured In2O3 was grown on TiO2 NPs by thermal treatment of the solids mixture of TiO2 with the parent In(OH)3. The effect of calcination temperature in the range between 400 °C and 700 °C was investigated and peculiar changes both in the structure and in the catalytic activity of the TiO2/In2O3 heterostructure were revealed. It was found out that T = 600 °C is the best operating temperature for hydrogen production and in combination with 3.5 wt% In2O3 the H2 production from water reached the value of 3.5 mmol/h.g irradiating in the UV–Vis region. Once 5.0 wt% Cu2O nanoparticles were loaded on TiO2/In2O3, the photocatalytic activity boosted to 9.6 mmol/h.g of H2, overcoming the hydrogen production of pristine TiO2 by a factor of 48. This result can be attributed to the formation of a highly efficient heterojunction that assures a synergistic cooperation among the three semiconductors yielding an improved charge separation and faster charge transport, as evidenced by Mott-Schottky, PL and EIS measures.

TiC and (Ti,Nb)3SiC2 based dual-layer coating on SUS430 for solid oxide fuel cell interconnects

TiC and crystalline (Ti,Nb)3SiC2 based dual-layer is prepared on SUS430 alloy by DC magnetron sputtering followed by annealing at 1000 °C for 20 h. The oxidation of TiC/TNSC coated alloy at 800 °C for 500 h follows the parabolic law with a low rate constant of 5.4 × 10−15 g2 cm−4 s−1. The formed oxide scale is composed of Cr2O3/MnCr2O4 dominated inner layer and outer layer of Nb-doped TiO2 and SiO2 uniform mixture. Owing to the barrier effect of TiC layer and dense oxide scale, outward diffusion of Cr and Mn is efficiently suppressed, resulting in the low Cr content in the outer oxide layer, which is beneficial to the reduced volatilization of Cr oxide. Furthermore, the ASR of the formed oxide scale at 800 °C is 15.87 mΩ cm2, suggesting excellent conductivity. It is concluded that the TiC/(Ti,Nb)3SiC2 coating can significantly improve the oxidation resistannce and electrical property of SUS430 alloy, endowing it potential application as SOFC interconnect protective coating.

One-step synthesis of single-phase, bulk Bi2Ti2O7 pyrochlores by deep undercooling rapid solidification and its formation mechanism

Preparation of dense Bi2Ti2O7 ceramics with single-phase pyrochlore structure is challenging using the conventional sintering method due to its thermal instability at ≥ 650 °C. Here we synthesized dense and phase-pure Bi2Ti2O7 ceramics from a mixture of Bi2O3 and TiO2 by a novel deep undercooling rapid solidification method using the aerodynamic levitation technique. We reported a surprising discovery that the pyrochlore phase can exist with Bi/Ti ratio varying between 0.9 and 1.1. By a comprehensive investigation on the phase purity, crystal structure, oxidation states and electrical properties, we revealed that the pyrochlore structure is primarily stabilized by the solidification process rather than presence of a large amount of Ti3+. With the advantages of being containerless, one-step and fast processing, deep undercooling rapid solidification is an effective and efficient approach to prepare dense Bi2Ti2O7 pyrochlores, and can be expanded to other thermally unstable compounds to obtain bulk materials.

Pengaruh Suhu Terhadap Sifat Listrik Polimer Konduktif Polianilin TiO2 Berpenguat Nano Serat Pinang

This research serves to see the effect of temperature on conductive polymers, and the temperature variations used are 27 ℃, 37 ℃, 47 ℃, 55 ℃, 67 ℃, and 77 ℃. The polyaniline used is pure polyaniline and a mixture of polyaniline, TiO2, and nano areca fiber with a mixture percentage of 70%: 27%: 3%. Polyaniline is produced from polymerization of aniline monomer and ammonium peroxydisulfate and nano arecafibers are used from nano arecafibers that have been produced in previous research. Electrical properties testing consisted of electrical conductivity and capacitance tests using an LCR meter. The results showed the lowest conductivity value at 27 ℃ was 0.18 × 10-2 S /cm, and the highest conductivity value at 77 ℃ was 1.22 × 10-2 S/cm for pure polyaniline, while the mixed polyaniline obtained the lowest conductivity value at 27 ℃ was 0,85 × 10-2 S/cm, and the highest value at 77 ℃ was 3.61 × 10-2 S/cm. For the capacitance test, the highest value was obtained at 6.8 μF and 18.9 μF. From the results obtained, the higher the temperature, the higher the conductivity value produced, while the capacitance results show that the higher the temperature used, the lower the capacitance value.

Reusable magnetic mixture of CuFe2O4-Fe2O3 and TiO2 for photocatalytic degradation of pesticides in water.

Photocatalysis is a promising treatment method to remove pollutants from water. TiO2-P25 is a commercially available model photocatalyst, which very efficiently degrades organic pollutants under UVA light exposure. However, the collection and the recovery of TiO2-P25 from cleaned water poses significant difficulties, severely limiting its usability. To address this challenge, we have prepared a sintered mixture of TiO2-P25 nanomaterials and magnetic CuFe2O4-Fe2O3 nanocomposites. The mixture material was shown to contain spinel ferrite, hematite and maghemite structures, copper predominantly in Cu2+ and iron predominantly in Fe3+ state. The CuFe2O4-Fe2O3 and TiO2-P25 mixture demonstrated magnetic collectability from processed water and photocatalytic activity, which was evidenced through the successful photodegradation of the herbicide 2,4-D. Our findings suggest that the sintered mixture of CuFe2O4-Fe2O3 and TiO2-P25 holds a promise for improving photocatalytic water treatment, with the potential to overcome current photocatalyst recovery issues.