Titanium Dioxide TiO2 Research Articles

Charge carrier dynamics of chemical vapor deposited carbon-doped titanium dioxide photoanodes

This study explores the synthesis of carbon-doped titanium dioxide TiO2(C) photoanodes through a single-step, low-pressure chemical vapor deposition (LCPVD) method, investigating the influence of carbon doping and oxygen vacancies on photoelectrochemical performance. The research employs morphological, structural, and photoelectrochemical characterization methods, including intensity-modulated photocurrent spectroscopy (IMPS) and distribution of relaxation times (DRT) analysis. We correlate the simultaneous presence of surface carbon and oxygen defects to improved charge separation and collection for TiO2(C) photoanodes. This work provides a comprehensive and detailed explanation of the photoelectrochemical performance of TiO2 electrodes, showing the potential behind combined IMPS-DRT analysis for photoelectrode characterization.

Sol-Gel Synthesis of TiO2 with Pectin and Their Efficiency in Solar Cells Sensitized by Quantum Dots.

In this study, titanium oxide TiO2 nanoparticles were produced using the sol-gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO2 nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption (UV-Vis) and the BET method. The structure and morphology of the TiO2 powder were described with SEM, revealing uniform monodisperse grains with a distribution of 80% regarding sizes < 250 nm; the resulting crystal phase of synthetized TiO2 was identified as an anatase and rutile phase with a crystallinity size estimated between 27 and 40 nm. Also, the surface area was determined by nitrogen adsorption-desorption using the Brown-Emmet-Teller method, with a surface area calculated as 19.56 m2/g, typical of an IV type isotherm, indicating mesoporous NPs. UV-Vis spectra showed that sol-gel synthesis reduced the band gap from the 3.2 eV common value to 2.22 eV after estimating the optical band gap energy using the adsorption coefficient; this translates to a possible extended photo response to the visible region, improving photoactivity. In addition, the power conversion of the photoelectrode was compared based on similar assembly techniques of TiO2 electrode deposition. Quantum dot crystals were deposited ionically on the electrode surface, as two different paste formulations based on a pectin emulsifier were studied for layer deposition. The results confirm that the TiO2 paste with TiO2-synthesized powder maintained good connections between the nanocrystalline mesoporous grains and the deposited layers, with an efficiency of 1.23% with the transparent paste and 2.27% with the opaque paste. These results suggest that pectin could be used as a low-cost, functional sol-gel catalysis agent for the synthesis of controlled NPs of metal oxide. It demonstrates interesting optical properties, such as an increase in photo response, suggesting further applications to photocatalysts and biomedical features.

Study of Microstructure, Morphology and Functional Groups of Titanium Dioxide (Tio2) Impregnated With Copper (Cu)

This research aims to determine the differences in the microstructure, morphology, and functional groups of TiO2 (P-25) after being impregnated with Cu. Cu-impregnated TiO2 samples are synthesized using the impregnation method with TiO2 (P-25) and copper sulfate as precursors. The microstructure and functional groups of TiO2 (P-25) and Cu-TiO2 were investigated using X-ray diffraction (XRD), scanning electron microscope-energy dispersive x-ray (SEM-EDX), and Fourier transform infrared (FTIR) analysis. The lattice parameters (a, b, and c) of the TiO2 sample were found to be a = b = 0.3778 nm, c = 0.9494 nm, and these values increased to a = b = 0.3779 nm, c = 0.9496 nm after the addition of Cu. The distance between the lattices of the TiO2 sample was measured at 0.3505 nm and increased to 0.3509 nm after Cu addition. The average crystallite size of the TiO2 sample was 33 nm, which increased to 43 nm after Cu impregnation. The strain value decreased from 2.76×10^(-3) to 1.82×10^(-3) after Cu addition. SEM results revealed that the morphology of the particles from the Cu-doped synthesis showed agglomeration. The success of Cu doping was confirmed by EDX mapping, which showed the presence of Ti, O, and Cu evenly distributed on the TiO2 surface. The FTIR spectrum indicated that TiO2 (P-25) and Cu-TiO2 particles had absorption peaks at similar wave numbers. However, in the absorption area of 1000 cm^-1 to 1250 cm^-1, new absorption bands affiliated with Cu-O bonds appeared in the Cu-TiO2 sample, resulting from TiO2 vibrations after Cu addition.

Study the Influence of Tin Oxide SnO2 Doping on the Optical and Structural Properties of Titanium Oxide TiO2

Titanium dioxide thin films, along with varying tin oxide ratios, were applied onto quartz substrates through pulsed laser deposition. The samples included pure TiO2 and doped versions ranging from 5% to 25%. The deposition parameters were kept constant at an energy level of 1000 mJ and a frequency of 6 Hz. Analysis via atomic force microscopy revealed that higher doping percentages correlated with increased surface roughness and grain diameter, indicating larger particle growth. Additionally, the absorption coefficient rose with higher doping ratios, peaking at 25% SnO2. This increase in absorption coefficient accompanied a decrease in the optical energy gap due to thicker film deposition, leading to higher absorbance and lower transmittance.

Non-Darcian MHD flow of ternary-hybrid Cu-TiO2-Al2O3/H2O nanofluid over an inclined sheet with activation energy

This study has been carried out to understand the unsteady MHD slip flow of a water-based ternary hybrid nanofluid including spherical Cu, titanium dioxide TiO2 and cylindrical Al2O3 nanoparticles across an angled sheet. The complicated scenario above investigates how ternary-hybrid nanofluid behaves when it is stretched across an inclined surface in the existence of a magnetic field. In complex thermal systems such as energy-generating technologies and cooling mechanisms, an understanding of this relationship is essential. In the existence of first-order velocity slip, the heat transfer has been examined taking into account the non-Darcy Porous media, activation energy, and heat source. The study is more accommodating because of the Soret effect. The relevant similarity transformations are applied in primary equations and a built-in bvp4c program is employed for solutions. The effectiveness of the numerical approach is demonstrated by a thorough agreement with results that have been published in the past. The key conclusions are as follows: greater values of the first order slip parameter cause the flow to slow down; an increase in Soret number causes the flow to speed up; and in both scenarios—that is, with and without velocity slip, fluid movement drops caused by higher values of the chemical reaction. The Forchheimer parameter lowers fluid velocity while activation energy enhances the fluid concentration.

Temperature-dependent optical bandgap of TiO2 under the Anatase and Rutile phases

A crucial step in developing new and/or more efficient devices relies on the detailed knowledge of the properties of their main (elemental or combined) parts. The same applies to titanium dioxide TiO2 that forms the basis of today numerous applications whose performances are determined by the presence or relative amount of the Anatase (A-) and Rutile (R-) most common phases of TiO2. Whereas the basic structural characteristics of these two polymorphs are very well-established, some of their optical aspects still deserve attention. With these ideas in mind this work presents a comprehensive investigation of the optical bandgap Egap of TiO2 under the Anatase and Rutile phases. The study considered pure A-TiO2 and R-TiO2 samples in the form of powder, and optical reflectance and Raman spectroscopy in the 83–823 K temperature range. In addition to reliable Egap values the study explores their temperature-dependent Egap(T) behavior that is expected to assist future advancements in the field of TiO2-based materials and devices (thin films, interfaces, low-dimensional systems, and photocatalytic and solar cells, for example).

Design and Fabrication of DSSC and Monitoring Using Embedded System

Fossil fuel shortages, increasing prices of crude oil, and the shunning of conventional energy sources (such as coal or nuclear power plants) are some of the factors that have made sustainable forms of traditional energy gain more attention. Some examples include hydropower, wind power, geothermal power, and biomass processing. Solar power is also a very important source of alternative energy. To comprehend such improving progress in achieving higher solar-to-electricity efficiency and improved long-term operating stability, the development process and basic principles for DSSCs should be understood. An FTO electrode with titanium dioxide (Tio2) is being used here, as part of which we grow dye tuned to give the required color and conductivity. It is called an anode. A pencil was used to graphite the other FTO glass, which would then serve as the cathode. We are presently working on using an iodide electrolyte. Also, current density and voltage were monitored by the ESP8266 kit. Key Words: Dye-sensitized solar cell; Carotenoid Extract; Electrolyte; ESP8266.

Graphene oxide-titanium oxide-polyaniline hybrid materials for high-performance dye-sensitized solar cells

A new solar cell that comprises a graphene oxide and titanium oxide nanoparticle (NP) composite with graphitized polyaniline (PANI) has been tested in polymer solar cells (PSCs). In this study, a series of conjugated polymers were synthesized and evaluated as the absorber and hole-transport layer materials in organic solar cells, demonstrating the significant impact of the chemical structure of the polymers on solar cell performance. The incorporation of graphene oxide (GOX) and titanium oxide TiO2 NP in conjugated polymers, particularly when graphitized within the PANI layer, led to improved open-circuit voltages compared to structurally similar polymers without NP. The morphology of the composite films was analyzed and related to the photovoltaic performance of polymers synthesized with polyaniline PANI-base and PANI-salt. Optimal NP addition in PANI-salt, PANI-base, PANI-base-TiO2, and PANI-base-GOX resulted in open-circuit voltages and efficiencies of 433 mV and 3.67%, 250 mV and 0.595%, 310 mV and 1.358%, and 520 mV and 2.366%, respectively. This study underscores the importance of polymer film uniformity in the performance of PSCs, with the highest efficiency obtained using a conjugated polymer with the best PANI-salt and PANI-base-GOX films. The research sheds light on the relationship between polymer structure and device photovoltaic performance, which is crucial for the design of new polymeric materials for efficient use and stable OSCs and PSCs.

Enhanced osteogenic response by collagen type I coating on surface-modified titanium bone implants

Surface modifications of titanium (Ti) bone implants can activate an osteogenic response and accelerate osseointegration after implantation. In this study, in vitro tests were performed to evaluate different titanium dioxide TiO2 modified surfaces, sandblasted, large grit, acid-etched implant surfaces and surfaces featuring nanotubular structures (nanopore diameters of 20 and 100 nm) produced through potentiostatic anodization before and after subjecting them to covalent treatment for functionalization and subsequent coating with collagen type I (Col I). The physicochemical and morphological properties were evaluated using spectroscopy and microscopy, which confirmed the structural and biochemical modifications of the surfaces after coating with Col I. Studies with pre-osteoblastic MC3T3-E1 cells indicate improved cell adhesion and proliferation on surfaces coated with Col I, whereas cell viability remained similar for all evaluated surfaces. The results of alkaline phosphatase expression and activity, as well as a mineralization assay, demonstrated that surfaces coated with Col I acted positively on the osteogenic differentiation of the cells in comparison with the non-coated surfaces. Our findings suggest that, regardless of the previous modification of the TiO2 surface, the addition of a Col I coating presents a promising modification for bone implant applications.

Immobilization of Bi2WO6 on Polymer Membranes for Photocatalytic Removal of Micropollutants from Water - A Stable and Visible Light Active Alternative.

In this work, bismuth tungstate Bi2WO6 is immobilized on polymer membranes to photocatalytically remove micropollutants from water as an alternative to titanium dioxide TiO2. A synthesis method for Bi2WO6 preparation and its immobilization on a polymer membrane is developed. Bi2WO6 is characterized using X-ray diffraction and UV-vis reflectance spectroscopy, while the membrane undergoes analysis through scanning electron microscopy, X-ray photoelectron spectroscopy, and degradation experiments. The density of states calculations for TiO2 and Bi2WO6, along with PVDF reactions with potential reactive species, are investigated by density functional theory. The generation of hydroxyl radicals OH• is investigated via the reaction of coumarin to umbelliferone via fluorescence probe detection and electron paramagnetic resonance. Increasing reactant concentration enhances Bi2WO6 crystallinity. Under UV light at pH 7 and 11, the Bi2WO6 membrane completely degrades propranolol in 3 and 1 h, respectively, remaining stable and reusable for over 10 cycles (30 h). Active under visible light with a bandgap of 2.91eV, the Bi2WO6 membrane demonstrates superior stability compared to a TiO2 membrane during a 7-day exposure to UV light as Bi2WO6 does not generate OH• radicals. The Bi2WO6 membrane is an alternative for water pollutant degradation due to its visible light activity and long-term stability.

Results of X-ray studies of titanium powder obtained for additive machines from OT4 alloy metal waste in alcohol

The results of experiments aimed at conducting X-ray studies of powders obtained by electrodispersing titanium alloy OT4 metal waste in alcohol are presented. It is noted that the particles of the electroerosion powder consist of titanium and aluminum, which form phases of pure titanium α-Ti, titanium oxide TiO and intermetallic Ti3Al. The conducted studies have shown that by the method of electroerosive dispersion of metal waste of the OT4 alloy, it is possible to obtain spherical titanium powders for additive machines of the required fractional composition from secondary raw materials in small batches with minimal energy consumption and minimal damage to the environment.

Assessing the effect of adding TiO2 and calcined montmorillonite clay nanoparticles on the mechanical properties of cement mortar

The study analyses the influence on the mechanical strength of titanium dioxide TiO2 and calcined montmorillonite (CMMT) particles added individually and combined to cement mortar mixes. Having both similar and complementary properties, the combined solution of TiO2 and CMMT nanoparticles can induce positive effects on the overall properties of cementitious composites. However, this combination has been tackled only in a couple of studies, with different approaches regarding the design mix, but without comparing the results with the individual-nanomaterial mixes. In this study, the bulk density, flexural strength, compressive strength, and material microstructure were analyzed at 28 days of curing, for an addition of 0.5 wt% and 0.75 wt% TiO2, of 1 wt%, 1.5 wt% and 2 wt% calcined montmorillonite (CMMT), and of nanomaterial combinations. From the flexural strength point of view, the CMMT-modified cement mortar mix registered the highest value of all modified mixes for a cement replacement of 1.5 wt%, reaching a 10.27% improvement compared to the reference mix. The highest compressive strength was recorded for the mix comprised of 1 wt% CMMT and 0.75 wt% TiO2, with an increment of 3.19% compared to the reference mix. The obtained results were confirmed by means of Scanning Electron Microscopy (SEM) investigations showing that the highest amount of CSH was observed for 1% wt% CMMT and 0.75% wt% TiO2, corresponding to the highest compressive strength value.

Preparation of synthetic rutile from Rosetta ilmenite concentrate

The hydrometallurgical procedure is suggested in this work to upgrade the ilmenite mineral which is separated from black sand at Rosetta, Egypt, to obtain high TiO2. The ilmenite concentrate is subjected to a digestion process using sulfuric acid solution in the presence of date molasses. Date molasses is chosen as new, cheap, eco-friendly and effective reductant. The relevant factors for titanium and iron dissolution from ilmenite concentrate include: the acid concentration, sample/acid ratio, reaction time, temperature in addition reductant percentage. These factors are studied and optimized. The optimum conditions are realized at 10 M H2SO4 acid with a solid/liquid ratio of 1/10 at 120 °C for 2 h in the presence of a definite amount of date molasses. Under these conditions, titanium and iron leaching efficiencies are attained at 98.4% and 92.8%, respectively. The resultant leach liquor is then subjected to a hydrolysis step for titanium separation as Ti(OH)2, dried at 110 °C and ignited at 850 °C to obtain high-grade titanium oxide (93.5%) TiO2.

Photocatalytic degradation of methylene blue dye from aqueous solution using TiO2 doped Activated carbon

The effluent coming out from the textile, paper and food industries containing dye is strongly coloured and reveals very harmful effects on living beings. In order to reduce wastewater pollution, the degradation of dye into non-toxic form is desirable. The photo catalytic degradation of methylene blue is reported in the present study. The irradiation of aqueous solution of methylene blue dye in presence of photo catalyst and UV light was carried out in the batch photo reactor. Titanium dioxide TiO2 /CFAC was used as photo catalyst for the study. The rate of decolorisation was estimated from residual concentration spectrophotometrically. Effects of various operating parameters such as the irradiation time, initial pH and the amounts of catalyst on the degradation of the dyes were investigated. Results show that the degradation kinetics fitted well to pseudo second order rate law. The maximum decolorizing efficiency occurred in less than 50min with 50mg of TiO2 /CFAC catalyst dose.

UV filter occurrence in beach water of the Mediterranean coast - A field survey over 2 years in Palavas-les-Flots, France.

A 2-year sampling campaign was realized on French Mediterranean beach (Palavas-les-Flots Hérault) in order to measure the concentration of UV filters released from the sunscreen used by bathers. Multiple factors suspected of playing determining roles in the UV filter pattern in water were explored, such as the seasonal and daily time evolutions, or the vertical and horizontal distributions, and they were regarded through the UV filter characteristics. The beach was monitored during periods of high and low tourist attendance, typically before, during and after the summer peak. The beachgoers attendance was counted. Bathing water was sampled distinctly from the bulk column and from the top surface layer, testing different sampling tools. Sediments and mussels were also sampled and analysed as potential UV filter sinks. Three organic UV filters (octocrylene OCR, avobenzone BMDBM and octyl methoxycinnamate OMC) and one mineral (titanium dioxide TiO2 ) were studied here as representatives of the current cosmetic market. Summer peak attendance on the beach was confirmed associated with peak levels of UV filter concentration in the bathing water, even more pronounced during a heat wave period. This relation was also observed at day scale with an afternoon peak, suggesting a rapid evolution of the UV filter pattern in water. Contrasted fates were measured between the four studied UV filters, that could be mainly explained by their respective characteristics, i.e. particulate or dissolved, hydrophilic or lipophilic, lifetime. Generally, this resulted in a concentration ranking TiO2 > OCR > OMC > BMDBM, ranging from 0.5 to 500 μg/L. The most lipophilic and recalcitrant OCR was found most vertically differentiated and over concentrated in the top surface layer of water. Finally, a large horizontal heterogeneity was also observed in the UV filter concentration pattern, raising the need for sample replicates that cover a significant area. This work fulfils some knowledge gaps on the issue of UV filter release in coastal environments, not only by providing original field data and methodological recommendations but also importantly in the comparison made of organic and mineral UV filters, which are often considered separately and rarely evaluated at the same time.

Synthesis of Carbon – TiC/TiB2 Composites at the Electrolytic Reduction of Fused Salts

This article presents the results of laboratory testing of the technology for the synthesis of composite carbon—titanium carbide/titanium diboride (C—TiC/TiB 2) material directly in course of electrolytic reduction of cryolite-alumina melts. After the preliminary standard treatment purposing the mixing of initial components—petroleum coke of different fractions, rutile titanium oxide TiO 2, boron oxide B 2 O 3 and binding agent—the cathode specimens were pressed to the specified sizes and thermally treated at the temperature of 1050 °С. Experiments with holding time of 5, 15 and 24 h during the electrolytic reduction process have demonstrated the acceptable wettability of cathode specimen surface. X-ray phase analysis and SEM-EDS-analysis have detected the presence of TiC/TiB 2 and titanium oxycarbide TiC x O 1-x within the volume of cathodes and on their surface. After 15 and 24 h experiments the aluminium layer with good adhesion to the surface was noticed on the cathode surface; which is indicative of wettability of the electrode with metal. This tested technology can be extended to the creation of wide range of composite products in the С—МеС/МеВ 2 system.

Fractal‐fractional analysis and numerical simulation for the heat transfer of ZnO + Al2O3 + TiO2/DW based ternary hybrid nanofluid

AbstractNanofluids are used to achieve maximum thermal performance with the smallest concentration of nanoparticles and stable suspension in conventional fluids. The effectiveness of nanofluids in convection processes is significantly influenced by their increased thermophysical characteristics. However, this technology is not ended here; binary and ternary nanofluids are now used to improve the efficiency of regular fluids. Therefore, this paper aims to analyze the natural convection Newtonian ternary nanofluid flow in a vertical channel. The tri‐hybridized nanoparticles of zinc oxide ZnO, Aluminum oxide Al2O3, and titanium oxide TiO2 is dissolved in base fluid distilled water (DW) to form a homogenous suspension. The impact of thermal radiation, joule heating, and viscous dissipation are also assumed. The classical Newtonian ternary nanofluid model has been generalized by using fractal‐fractional derivative (FFD) operator. The generalized model has been discretized by using the Crank–Nicolson scheme and then solved by using computational software. To analyze the behavior of fluid flow and heat distribution in fluid, the obtained solution was computed numerically and then plotted in response to different physical parameters. It is noted from the figure that when the volume fraction ϕ reaches to 0.04 (4% of the base fluid), the ternary nanofluid flow shows a significant amount of enhancement in heat transfer rate as compared to binary and unary nanofluid flows. This enhancement in the rate of heat transfer leads to improve the thermophysical characteristics such as viscosity, thermal expansion, and heat capacity etc. of the base fluid. It is also worth mentioning here that the thermal field is also enhance with the higher values of Eckert number , radiation parameter , and joule heating parameter .

Turbulence effects on the formation and growth of nano-particles in three-dimensional premixed and non-premixed flames

This study examines the impact of turbulence on particle-forming flames via three-dimensional direct numerical simulations. The simulations employ the finite rate chemistry approach to simulate both premixed and non-premixed methane-air turbulent planar jet flames. These flames are doped with titanium tetraisopropoxide (TTIP) to form titanium dioxide TiO2 nanoparticles. The sectional model is employed to solve the population balance equation governing particle dynamics. Through these simulations, a number of the Batchelor scales pertaining to the smaller nanoparticle structures are effectively captured. The analysis conducted on these simulations is to identify and quantify the respective influences of diffusion, coagulation, and inception on variations in particle concentration across different regions within the flame. Several regions of the computational domain with different turbulence intensities are analyzed. Results show that the physical mechanisms that contribute to particle growth are not negligible on the particle concentrations. The impact of normal aN and tangential aT strain rates, which govern the thickness of particle-loaded zones affected by turbulence effects, is also evaluated. Conditional mean values of the strain rates upon the particle number concentration fields and the PDFs of aN and aT confirm that on the iso-surfaces of the particle fields the compressive and stretching effects are predominant. The aforementioned information is used to gain a deeper understanding of the influence of turbulence on premixed and non-premixed particle-forming flames, which will help us to develop transferable models for the simulation of nanoparticle synthesis.

Influence of Low Temperature Plasma Oxidizing on the Bioactivity of NiTi Shape Memory Alloy for Medical Applications.

The present study elucidates the impact of glow discharge oxidation within a low-temperature plasma environment on the bioactivity characteristics of an NiTi shape memory alloy. The properties of the produced surface layers, such as structure (TEM observations), surface morphology (SEM observations), chemical and phase composition (EDS and XRD measurements), wettability (optical gonimeter), and the biological response of osteoblasts and platelets to the oxidized surface compared with the NiTi alloy without a surface layer are presented. The presented surface modification of the NiTi shape memory alloy, achieved through oxidizing in a low-temperature plasma environment, led to the creation of a continuous surface layer composed of nanocrystalline titanium oxide TiO2 (rutile). The findings obtained from this study provide evidence that the oxidized layer augments the bioactivity of the shape memory alloy. This augmentation was substantiated through the spontaneous biomimetic deposition of apatite from a simulated body fluid (SBF) solution. Furthermore, the modified surface exhibited improved osteoblast proliferation, and enhanced platelet adhesion and activation. This proposed surface modification strategy holds promise as a prospective solution to enhance the biocompatibility and bioactivity of NiTi shape memory alloy intended for prolonged use in bone implant applications.

Numerical investigation of magnetized nanofluid flow with thermal radiation and homogeneous/heterogeneous reactions over a vertical cylinder

Nanofluid flow has gained attention due to its promising applications in numerous industries. Nanofluids exhibit a significant advantage over conventional fluids due to their superior heat transfer capability, attributed to the presence of nanoparticles that enhance thermal conductivity, resulting in improved heat dissipation and efficiency. Current research aims to numerically investigate the impact of homogeneity and heterogeneity on the mixed convection flow of incompressible viscous nanofluids through a vertically permeable cylinder under suction/injection circumstances. The study also considers thermal radiation and heat source/sink phenomena. Ethylene glycol is utilized as base fluid, while nanoparticles include silicon carbide SiC and Titanium dioxide TiO2. The mathematical flow model, based on nonlinear partial differential equations (PDEs), is converted into ordinary differential equations (ODEs) by using suitable similarity transformations that pronounced nonlinear system of ODEs. To deal with this nonlinear system, the bvp4c and shooting methods are used in the commercial software MATLAB to solve these ODEs numerically. The impacts of flow parameters on various quantities of interest are elaborated graphically. From obtained results it is analyzed that velocity field boosts up versus higher values of nanoaprticle volume fraction. The velocity field is decreases with increasing the amount of magnetic field. An increase in the thermal field is observe with a rise in the thermal radiation parameter. The good agreement between current results and published work is noted.