Iron doped thin TiO2 films synthesized with the RF PECVD method

Iron doped titanium dioxide coatings were synthesized with the help of RF plasma enhanced CVD technique. As a source of titanium, titanium chloride (IV) TiCl₄ was used while iron pentacarbonyl (0) Fe(CO)₅ served as iron supply. The coatings were diagnosed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Their elemental and chemical composition was studied with the help of X-ray energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy, respectively. For the determination of their optical properties, variable angle spectroscopic ellipsometry (VASE) and ultraviolet-visible (UV-Vis) spectroscopy techniques were used. Iron content in the range of 0.07–11.5 at% was found in the films. Apart from oxygen, titanium and iron, a presence of trace amounts of chlorine, very likely originating from the titanium precursor, was recorded. FTIR studies showed that iron was built-in in the structure of TiO₂ matrix. Surface roughness, assessed using SEM and AFM techniques, increases with an increasing content of this element. VASE measurements revealed an increase of the coatings refractive index with a growing iron concentration, with the extinction coefficient remaining low and independent of that parameter. Trace amounts of iron resulted in a lowering of an absorption threshold of the films as well as their optical gap, but the tendency was reversed for high concentrations of that element.     

Morphology,structure and photowettability of TiO2 coatings doped with copper and fluorine

The work reports synthesis, structure and properties of doubly doped titanium dioxide coatings activated by ultraviolet and visible light. Copper within a concentration range of 0.4–3.4 at% and fluorine within a concentration range of 1.7–9.4 at% were introduced as dopants. The coatings were prepared with the help of radiofrequency plasma enhanced chemical vapor deposition technique with a single precursor compound providing both dopants and titanium (IV) chloride being a source of titanium. Elemental composition and chemical bonding analyses of the coatings were carried out with the help of X-ray photoelectron spectroscopy. The results indicate that both admixtures are chemically bound to the TiO₂ matrix – a notion confirmed by Fourier transform infrared spectroscopy. Phase composition studies, performed with a low angle X-ray diffraction method, revealed a presence of a threshold concentration of the dopants affecting the coatings crystallinity. Surface morphology and its topography were studied with the help of scanning electron microscopy and atomic force microscopy. Several coatings exhibited a superhydrophilic effect upon relatively short time of illumination.     

Prepare SiTiOC ceramic coatings by laser pyrolysis of titanium organosilicon compound

A SiTiOC ceramic coating with outstanding tribological performance was prepared by laser scanning the organosilicon coating with different laser power. The composition and structure of the obtained SiTiOC ceramic coatings were analyzed by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), Raman spectra, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The tribological performance of the coatings was studied using a multi-functional reciprocating friction and wear tester. The results showed that the chemical structure (chemical bonding) of the coatings prepared at 0 W, 350 W, and 500 W laser powers included Si-O-Si, Si-C, and TiO₂, while that prepared at 800 W was mainly composed of amorphous SiO₂, indicating that the coating had higher ceramization. The SiTiOC ceramic coatings prepared by the present process effectively reduced the friction coefficient and wear volume of the steel substrate, which indicated that they had good anti-friction and wear resistance properties.     

Morphology of carbon/TiC composite films prepared by carbonization of polyimide/titania composites

Polyimide/titania (PI/TiO₂) composite was synthesized by in situ sol–gel polymerization, and carbon/titanium carbide (TiC) composite films were prepared by carbothermal reduction of the PI/TiO₂ composite at 1,600 °C under flowing argon. The structure and properties of the composites were studied by wide angle X-ray diffraction (WAXD), Fourier transform infrared spectrometer (FTIR), scanning electron microscopy, and energy dispersive X-ray spectroscopy. The carbon/TiC composite films exhibited metallic luster on the surface and compact structure in cross section with well dispersed TiC particles. WAXD intensity distribution revealed that TiC particles formed by tightly bonding between elemental carbon and titanium formed crystallites which as a filler provided tough films. The results indicated that heat treatment of PI/TiO₂ under argon is a promising method for preparing tough carbon composite films.     

Optical and structural properties of cost-effective nanostructured calcium titanate blue phosphor

The current study reports nanostructured CaTiO₃ powder produced by two different novel modified sol-gel methods. The chemical reaction between the calcium oxide (CaO) extracted from chicken eggshell (ES) and titanium (IV) isopropoxide (TTIP) leads to the synthesis of calcium titanate nanopowder. Further leaf extract has also been added in one method which shows the significant effect to reduce particle size up to a certain extent. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM) were examined to confirm the nanometric particle size. Further, the crystalline structure and phase involvement were also investigated by Rietveld refinement. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis), and photoluminescence spectra (PL) characterization were used to study the functional groups, elemental composition, and optical properties of the material. The photoluminescence emission that occurred in the sample was due to the distortion between [TiO₆] – [TiO₆] complex clusters causing a difference in the charge density, which can promote a charge transfer between these clusters. The CIE chromaticity coordinates were determined and it shows that the synthesized sample is a promising candidate for the blue color phosphor application. The present phosphors were highly useful for UV chip excited white LED applications.     

Enhanced visible light-induced photoelectrocatalytic degradation of phenol by carbon nanotube-doped TiO2 electrodes

We used a modified sol-gel method to prepare titanium dioxide and multi-walled carbon nanotube (CNT) composites that we subsequently deposited onto indium tin oxide (ITO) conductive glass plates. We characterized these CNT-doped TiO₂ (CNT-TiO₂) films using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and diffuse reflectance UV-vis spectroscopy. The photoelectrocatalytic (PEC) activity of the composites was evaluated through their ability to mediate the degradation of phenol. XRD measurements indicated that the TiO₂ component existed solely in the anatase phase and that the crystallinity of the CNTs was low. XPS indicated that carbon atoms could substitute for both oxygen and titanium atoms in the TiO₂ lattice to form Ti-C and Ti-O-C structures, which were responsible for the extra photoabsorption and PEC activity under illumination with visible light, in addition to those provided by the CNTs and carbonaceous and Ti³⁺ species. An interphase interaction between TiO₂ and the CNTs elevated the photoabsorbance of the composites in the visible light region. A sample of TiO₂ doped with 10% CNTs and calcined at 400 °C exhibited the highest photocurrent and PEC efficiency. We systematically investigated the effects of several parameters of the PEC process, including the applied potential and pH, on the phenol conversion.     

Synthesis of nitrogen-doped carbon coated TiO2 microspheres and its application as metal support in cinnamaldehyde hydrogenation

N-doped carbon coated TiO₂ microspheres (CNx/TiO₂) were synthesized by the carbonization of the polypyrrole (PPy) coating on the surface of TiO₂ microspheres and used as support to disperse Pt and PtCo nanoparticles for investing the selective hydrogenation of cinnamaldehyde. The support and catalysts have been characterized in terms of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The hydrogenation results showed the conversion increased with an increase of CNx amount until the CNx coated TiO₂ microspheres completely.     

Effect of electrolyte on the supercapacitive behaviour of copper oxide/reduced graphene oxide nanocomposite

Cupric oxide/reduced graphene oxide (CuO/rGO) nanocomposites were synthesized through a chemical reduction method using hydrazine hydrate as the reducing agent. The morphology, elemental composition, and bonding network of the CuO/rGOnanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy respectively. The XRD results reveal lattice spacing and lattice strain from 3.371 to 3.428 Å and 1.05 × 10⁻³to 5.44 × 10⁻³ respectively, with the increasing ratio of rGO: CuO from 1:1 to 1:5. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)and galvanostatic charge-discharge (GCD) studyofCuO/rGOas the electrode material showed excellent super-capacitive behavior in H₂SO₄ over Na₂SO₄ electrolytes. Moreover CuO/rGO nanocomposites exhibited better capacitance retention in H₂SO₄(75.69%) compared to Na₂SO₄(12.06%).     

Deposition of HMDSO-based coatings on PET substrates using an atmospheric pressure dielectric barrier discharge

This paper presents results on the formation of coatings in an atmospheric pressure dielectric barrier discharge using hexamethyldisiloxane (HMDSO) as gaseous precursor. Plasma-polymerized films are deposited onto polyethylene terephthalate (PET) films using argon and argon/air mixtures as carrier gases. The chemical and physical properties of the obtained coatings are discussed in detail using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). FTIR and XPS results show that the composition of the gas phase and the chemical structure of the obtained coatings are clearly correlated. When pure argon is used as working gas, the film is polymeric with a structure close to [(CH₃)₂–Si–O]_n, which means that the deposited films resemble PDMS. However, if plasma-polymerization occurs in argon/air mixtures, the deposited film is silica-like containing only few carbon atoms. These dense SiO_x coatings generally exhibit high barrier properties, while pure HMDSO-derived films might be of importance for selective permeation. From this point of view, the capability of controlling the film composition by varying the operation conditions opens interesting perspectives.     

Template-free preparation of TiO<Subscript>2</Subscript> microspheres for the photocatalytic degradation of organic dyes

TiO₂ microspheres were successfully synthesised by simple solution phase method by using various amount of titanium butoxide as precursor. The prepared TiO₂ were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance absorption spectra (UV-DRS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XRD analysis revealed that the as-synthesized TiO₂ microsphere poses an anatase phase. The photocatalytic degradation experiments were carried out with three different dyes, such as methylene blue, brilliant black, reactive red-120 for four hours under UV light irradiation. The results show that TiO₂ morphology had great influence on photocatalytic degradation of organic dyes. The experimental results of dye mineralization indicated the concentration was reduced by a high portion of up to 99% within 4 hours. On the basis of various characterization of the photocatalysts, the reactions involved to explain the photocatalytic activity enhancement due to the concentration of titanium butoxide and morphology include a better separation of photogenerated charge carriers and improved oxygen reduction inducing a higher extent of degradation of aromatics.     

Synthesis of hexagonal boron carbonitride phase by solvothermal method

A solvothermal reaction of CH₃CN·BCl₃ and lithium nitride (Li₃N) using benzene as the solvent has been successfully applied to prepare boron carbonitride at 300 °C and less than about 7 MPa. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) are used to confirm their chemical composition and atomic-level hybrid. X-ray diffraction (XRD) and transmission electron diffraction (TED) analysis indicate that the powders have hexagonal network structures.     

The synthesis and morphology characteristic study of BAO-ODPA polyimide/TiO2 nano hybrid films

Hybrid nanocomposite films of titanium dioxide (TiO₂) in polyimide (PI) from 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole (BAO) and 4,4′-oxydiphthalic anhydride (ODPA) have been successfully fabricated by an in situ sol-gel process. These nanocomposite films exhibit fair good optical transparency up to 40 wt% of TiO₂ content. X-ray diffraction spectroscopy shows three sharp peaks in pure BAO-ODPA PI. It results from the intermolecular regularity. However, the intermolecular regularity in the hybrid film is disrupted by the introduction of TiO₂ nanoparticles with no sharp peak in XRD spectra. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results confirm the formation of TiO₂ particles in PI matrix. The surface Ti content is much lower than the theoretical bulk content in all hybrid films. The ratio of the former to the latter increases with the TiO₂ content and levels off at TiO₂ wt%≥20. Transmission electron microscope (TEM) images show that the TiO₂ phase is well dispersed in the polymer matrix. The size of the TiO₂ phase increases from 10 to 40 nm when the TiO₂ content is 5-30 wt%, respectively.     

Synthesis and characterization of polythiophene/titanium dioxide composites

Polythiophene/titanium dioxide (PT/TiO₂) composites were prepared by the in situ chemical oxidative polymerization method. The resulting PT/TiO₂ composites were characterized by Fourier transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM). UV–Vis diffuse reflectance spectra measurements show that the PT/TiO₂ composites can adsorb light of wavelengths ranging from 200 nm to 800 nm. The PT/TiO₂ composites showed good adsorption properties and were more efficient in removing dye from solution than pure PT and pure TiO₂. The PT/TiO₂ composites exhibited photocatalytic activities to some extent under UV light illumination.     

The effect of lignin on the structure and characteristics of composite coatings electrodeposited on titanium

Composite coatings based on lignin, obtained by electrophoretic deposition (EPD) on titanium, were investigated. The aim of this work was to produce hydroxyapatite/lignin (HAP/Lig) coatings on titanium and to investigate the effect of the lignin concentration on microstructure, morphology, phase composition, thermal behavior and cytotoxicity of the HAP/Lig coatings. An organosolv lignin was used for the production of the composite coatings studied in this research. The properties of HAP/Lig coatings were characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR) and X-ray photoelectron spectroscopy (XPS), as well as the MTT test of cytotoxicity. The results showed that higher lignin concentrations protected the HAP lattice during sintering, thereby improving the stability of the HAP/Lig coatings. The cell survival of peripheral blood mononuclear cells (PBMC) after proliferation indicates that the HAP/Lig coating with 1 wt% Lig electrodeposited on titanium was non-toxic with significant promise as a potential bone-repair material.     

Photocatalytic performance of Al and Nb-doped TiO2 nanoparticles prepared by microwave-assisted hydrothermal method

Microwave-assisted hydrothermal synthesis of aluminum (Al)-doped TiO₂ (ALT) and niobium (Nb)-doped TiO₂ (NBT) nanoparticles were carried out. Investigations were performed to examine the crystallinity, vibrational modes, surface morphology, and composition using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS), respectively. The XRD study indicated the higher crystallinity of the ALT particles compared to the Al and Nb-doped TiO₂ (ALNBT) particles, and only the presence of the anatase phase was observed in all samples. As a result of doping, the Raman mode at ∼147 cm⁻¹ is found to be shifted toward a higher wavenumber for both samples. SEM analysis showed the spherical morphology of ALT and NBT nanoparticles. The elemental composition peaks of Al, titanium, Nb, and oxygen were noticed by EDS measurements. Furthermore, both prepared nanoparticles were used as photocatalytic materials. The Nb and Al-doped samples showed an improvement in the photocatalysis response in relation to the pure TiO₂ sample, in which Al-doped sample was able to decolorize 100% of rhodamine B in 75 min of analysis.     

Preparation of super-hydrophilic amorphous titanium dioxide thin film via PECVD process and its application to dehumidifying heat exchangers

The super-hydrophilic amorphous titanium dioxide (TiO₂) thin film was prepared by plasma-enhanced chemical vapor deposition (PECVD) process for an application to dehumidifying finned-tube heat exchangers. The chemical components and surface structure were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). The wettability and long-term durability were investigated by measuring the water contact angle and by performing wet/dry cycles. The samples were subjected to 1000 times of wet/dry cycles to establish long-term durability. The water contact angle of the amorphous TiO₂ thin film was about 8° at as-deposited film with O₂ plasma treatment and was about 15° after 1000 wet/dry cycles. The amorphous TiO₂ thin film had excellent wettability and long-term durability under full wetting conditions.     

Spherical ferroelectric PbZr0.52Ti0.48O3 nanoparticles with high permittivity: Switchable dielectric phase transition with temperature

The spherical ferroelectric PbZr_0.52Ti_0.48O₃ (PZT 52/48) nanoparticles are prepared via simple and environment friendly high temperature solid state method. The crystal structure and morphology of these particles are characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM). XRD analysis and selected area electron diffraction (SAED) pattern of PZT particles revealed its crystalline nature. The energy involved in the synthesis especially during the initiation and termination processes for the formation of PZT particles is found from the high temperature calorimetric study. These particles are spherical in nature with an average diameter of ≤20 nm. The bulk and surface chemical composition of these particles are investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). XPS study reveals that the prepared PZT particles contain titanium ion in two different oxidation states namely Ti³⁺ and Ti⁴⁺. The PZT particles exhibit high permittivity with relatively low dielectric loss. From temperature dependent dielectric analysis, it is seen that there is a switchable dielectric phase transition at or above 80 °C.     

Synthesis and Photoelectric Property of Poly(3-Octylthiophene)/Titanium Dioxide Hybrid

A series of conducting polymer complexes of poly(3-octylthiophene) and titanium dioxide (POT/TiO₂) in different proportions were synthesized. X-ray diffraction patterns (XRD) indicated that the interplaner spacing of the composite samples is smaller than the pure TiO₂. X-ray photoelectron spectroscopy (XPS) and IR support a chemical interaction between POT and nano-TiO₂ in the complexes. Cyclic voltammetry (CV) showed that the energy gap of the POT/TiO₂ composite was 0.43 eV, which was smallest when the proportion was 1:1. Ultraviolet–visible spectra (UV–vis) and luminescence spectra (FL) showed that optical performance was far superior to both POT and TiO₂.     

Simple fabrication and photocatalytic activity of S-doped TiO2 under low power LED visible light irradiation

A series of S-doped TiO₂ with visible-light photocatalytic activity were prepared by a simple hydrolysis method using titanium tetrachloride (TiCl₄) and sodium sulfate (Na₂SO₄) as precursors. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectrophotometer (UV–Vis DRS), and X-ray photoelectron spectroscopy (XPS). With the doping of S, photocatalysts with small crystal size, high content of anatase phase were obtained. The result showed that S-doped TiO₂ demonstrate considerably high photoactivity under low power visible LED light irradiation, while undoped TiO₂ and the Degussa P25 have nearly no activity at all. The possible mechanism of S-doped for the visible-light activity was discussed.     

Preparation,characterization and the antimicrobial properties of metal ion-doped TiO2 nano-powders

TiO₂ samples doped with lithium, sodium, magnesium, iron or cobalt were prepared by high-energy ball milling for different periods of time. The crystalline phase, chemical composition, crystalline size and photo-absorption were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS) and Ultraviolet visible diffuse reflectance spectroscopy (UV - Vis - DRS), Fourier transform infrared spectroscopy (FT - IR) and scanning electron microscopy (SEM). The antimicrobial properties of the modified TiO₂ samples were evaluated with E. coli and S.aureus assays. The results of the XRD show that the TiOSO₄, Ti₃O₅, Li₂TiO₃ and NaTi₂O₄ phases appear along with Li, Na and Mg doped TiO₂. However, XPS spectra indicated that Ti exists as both Ti³⁺ and Ti⁴⁺ in Na-doped TiO₂ samples. Ti³⁺, due to its narrow band gap, is highly active in promoting visible light-induced photocatalytic activity. SEM images showed that the crystalline size of TiO₂ is reduced and has a common-round and hexagonal plate morphology after milling. The modified TiO₂ samples had the best antimicrobial activities after 3 h of milling. In particular, the antimicrobial rate of TiO₂ 5% doped with transition metals (Co, Fe) reached 100% against E. coli, but the antibacterial rate against S. aureus for Co and Fe dopants was 98.4% and 98.2%, respectively.