TiO2 Phase Research Articles

Electrochemical detection of oxaliplatin as an anti-cancer drug for treatment of breast cancer using TiO2 nanoparticles incorporated graphitic carbon nitride

Accurate and effective oxaliplatin (OXP) concentration detection is essential for maximizing therapeutic advantages and reducing negative effects of this anti-cancer therapy. Using a nanocomposite-based sensor, we present in this paper a novel method for electrochemical OXP detection. It is made of graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) nanoparticles embedded on a glassy carbon electrode (GCE) using the hydrothermal method. The X-ray diffractometer (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) structural investigations revealed that the g-C3N4-TiO2 nanocomposite material is composed of anatase TiO2 and g-C3N4 phases. Using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analyses, electrochemical tests demonstrated that g-C3N4-TiO2/GCE was a sensitive and selective OXP sensor. According to the results, the sensor has a linear range of 10 to 2030 μM, a sensitivity value of 0.04811μA/μM, and a detection limit of 0.010 μM. The recommended sensor's effectiveness in detecting OXP in prepared real samples from blood serum and urine samples of volunteers demonstrated significant recovery values (yielding recovery values exceeding 94.00%) and satisfactory precision (with a relative standard deviation of less than 4.23%), demonstrating that the g-C3N4-TiO2/GCE sensor was dependable and accurate for measuring OXP levels in serum and urine samples.

A New Approach on the Egyptian Black Sand Ilmenite Alteration Processes

Several studies have investigated the process of alteration of ilmenite, especially in black sand. To predict the mechanisms of ilmenite alteration and the role of some minor element oxides in the alteration process, separated non-magnetic altered ilmenite grains were examined using a binocular microscope and a Cameca SX-100 microprobe instrument. Twenty intergrown phases of alteration products were concluded in three postulated scenarios for the following alteration processes, carried out after forming the most stable lowest Leached pseudorutile (LPSR) phase FeTi3O6(OH)3. Most of the alteration phases of pseudorutile (PSR) and LPSR have real Ti/(Ti+Fe) ratios between 0.6 and 0.75. Some misleading calculations of definite analyzed ilmenite alteration spots showed that the analyzed TiO2 percentage is contained within the chemical formula of the analyzed LPSR phase. In these cases, the false Ti/(Ti+Fe) ratios attain up to 0.9, the false included total number of anions (O, OH) ranges between 7 and 8.5, and the associated molecular water ranged between half and two water molecules (0.5-2 H2O). In these cases, the structure of the remaining LPSR phase may be intergrown with a separated individual triple rutile phase, which appears to have the same X-Ray Diffraction (XRD) pattern as the single PSR phase, or intergrown with a cryptocrystalline TiO2 phase. Some molecular formulas of PSR or Hydroxylian PSR (HPSR) from previous studies were discussed and explained following the proposed approach.

Electronic Bulk and Surface Properties of Titanium Dioxide Studied by DFT-1/2.

Transparent conductive oxides, such as TiO2, are important functional materials for optoelectronic and photovoltaic devices. We investigate the electronic bulk properties of the TiO2 phases rutile and anatase with the DFT-1/2 method and obtain a quantitatively good description of their electronic band structures. We then applied this method to the (001) surfaces of rutile and anatase and calculated their ionization potentials (IPs) and work functions (WF). To relate these calculated surface properties with values from experiments, we evaluated the effect of varying the oxygen stoichiometry at the surface on both IP and WF.

Influence of sintering temperature on the mechanical properties and biocompatibility of titanium-nano hydroxyapatite functionally graded materials

Titanium-hydroxyapatite functionally graded materials (Ti/HA FGMs) exhibit potential for specific mechanical and biological properties. Spark plasma sintering (SPS) has attracted considerable attention in recent years as a flexible process for manufacturing Ti/HA FGMs with accurate gradients of composition and microstructure. However, little information has been discovered about how the sintering temperature affects the mechanical behavior and biocompatibility of Ti/HA FGMs produced via SPS. In this study, the relationship between sintering temperature and the mechanical and biocompatibility properties of the Ti/HA FGM created by SPS is explored. 6-Layer functionally graded Titanium-Nano hydroxyapatite specimens were produced at three sintering temperatures of 850, 1000, and 1150 °C. To investigate the properties of the specimens, various techniques including compression test, Vickers hardness, X-ray diffraction (XRD), toxicity (MTT), and cell adhesion were performed. According to the results, TiO2 and TCP phases formed in the structure of FGM by raising the sintering temperature to 1150 °C, which decreased the compressive strength from 265 to 167 MPa and increased the maximum hardness from 419 to 894 HV. In addition, increasing the sintering temperature to 1150 °C enhanced the biocompatibility of the fabricated Ti/HA FGM. The optimum sintering temperature for generating Ti/HA FGM with appropriate mechanical and biocompatibility properties was 1000 °C.

Ecofriendly alkali metal cations diffusion improves fabrication of mixed-phase titania polymorphs on fixed substrate by chemical vapor deposition (CVD) for photocatalytic degradation of azo dye

Controlling the nanoscale synthesis of semiconductor TiO2 on a fixed substrate has fascinated the curiosity of academics for decades. Synthesis development is required to give an easy-to-control technique and parameters for TiO2 manufacture, leading to advancements in prospective applications such as photocatalysts. This study, mixed-phase TiO2(B)/other titania thin films were synthesized on a fused quartz substrate utilizing a modified Chemical vapor depodition involving alkali-metal ions (Li+, Na+, and K+) solution pre-treatment. It was discovered that different cations promote dramatically varied phases and compositions of thin films. The films had a columnar structure with agglomerated irregular-shaped particles with a mean thickness of 800–2000 nm. Na+ ions can promote TiO2(B) more effectively than K+ ions, however Li+ ions cannot synthesize TiO2(B). The amounts of TiO2(B) in thin films increase with increasing alkali metal (K+ and Na+) concentration. According to experimental and DFT calculations, the hypothesized TiO2(B) production mechanism happened via the meta-stable intermediate alkaline titanate transformation caused by alkali-metal ion diffusion. The mixed phase of TiO2(B) and anatase TiO2 on the fixed substrate (1 × 1 cm2) obtained from Na+ pre-treated procedures showed significant photocatalytic activity for the degradation of methylene blue. K2Ti6O12, Li2TiO3, Rutile TiO2, and Brookite TiO2 phase formations produced by K+ and Li + pretreatment are low activity photocatalysts. Photocatalytic activities were more prevalent in NaOH pre-treated samples (59.1% dye degradation) than in LiOH and KOH pre-treated samples (49.6% and 34.2%, respectively). This revealed that our developed CVD might generate good photocatalytic thin films of mixed-phase TiO2(B)/anatase TiO2 on any substrate, accelerating progress in future applications.

Cost-effective production of radiation shielding coatings using multilayers of titania and silica

The presence of visible and infrared (IR) radiations available from solar radiation causes the temperature in the atmosphere to rise. Because of the temperature disparity, glass-walled buildings typically utilize air conditioners, increasing the generation of green-house gases in the environment. As a result, the application of reflection coating is required to safeguard the environment and limit the danger of greenhouse emissions. We present here the fabrication of a thermal insulating coating utilizing a multilayer TiO2/SiO2 structure that can reflect visible and infrared light with fewer layers of the aforementioned combination. X-ray diffraction was used to examine the as-fabricated structure on the glass substrate and found the anatase phase of TiO2 with the strongest peak at Bragg angle 25O. Fourier transform infrared spectroscopy was used to investigate the presence of TiO2 and SiO2 functional linkages, which were found at 904 cm−1, and 763 cm−1 wavenumbers respectively. Cross-sectional field emission scanning electron microscopy examinations on the fabricated five-layer (TiO2/SiO2/TiO2/SiO2/TiO2) multilayer structure revealed the presence of TiO2 and SiO2 with thicknesses calculated around 186/300/273/218/131 nm respectively. Furthermore, reflectance analysis on the as-fabricated multilayer structure demonstrated 90 % reflectance in the infrared spectral region, and 100 % in the visible region. As a result, developed coatings for glass furnishings were advised in order to not only deflect visible and infrared radiations from the sun spectrum and keep indoor temperatures cool without the use of air conditioners, but also to act as visible light communication boosters.

Investigation on Al-Al2O3 refractories with Al2O3-Ti2O3 raw material at evaluate temperatures

To explore the phase evolution and performance changes of Al-Al2O3 refractories at high temperature upon adding novel Al2O3-Ti2O3 raw materials, samples with different Al2O3-Ti2O3 contents were heated at 1300 and 1500 °C under N2 atomosphere. The samples were analyzed by XRD, SEM, TG-DSC,industrial CT. The results indicate that the reaction between Ti2O3 and Al proceeds at elevated temperatures under N2, and the Ti2O3 phase transformed from Al-Ti alloy to TiN. At 1300 ℃, Ti2O3 was party reduced by Al and formed Al-Ti alloys with the unreacted Al, and the remaining Ti2O3 was present in a finely dispersed state, exhibiting fine whiskers in the matrix. When the heating temperature increaseds to 1500 ℃, the whiskers in the matrix became coarse due to the gaseous Al2O phase, and Ti2O3 transformed into TiN through Al2O(g) migration. The cold compressive strength and bending strength at ambient temperature of the heated samples were significantly improved.

Structural and Electromagnetic Signatures of Anatase and Rutile NTs and Sheets in Three Different Water Models under Different Temperature Conditions.

Experimental studies of TiO2 nanotubes have been conducted for nearly three decades and have revealed the remarkable advantages of this material. Research based on computer simulations is much rarer, with research using density functional theory (DFT) being the most significant in this field. It should be noted, however, that this approach has significant limitations when studying the macroscopic properties of nanostructures such as nanosheets and nanotubes. An alternative with great potential has emerged: classical molecular dynamics simulations (MD). MD Simulations offer the possibility to study macroscopic properties such as the density of phonon states (PDOS), power spectra, infrared spectrum, water absorption and others. From this point of view, the present study focuses on the distinction between the phases of anatase and rutile TiO2. The LAMMPS package is used to study both the structural properties by applying the radial distribution function (RDF) and the electromagnetic properties of these phases. Our efforts are focused on exploring the effect of temperature on the vibrational properties of TiO2 anatase nanotubes and an in-depth analysis of how the phononic softening phenomenon affects TiO2 nanostructures to improve the fundamental understanding in different dimensions and morphological configurations. A careful evaluation of the stability of TiO2 nanolamines and nanotubes at different temperatures is performed, as well as the adsorption of water on the nanosurface of TiO2, using three different water models.

Interfacial microstructure and mechanical properties of joints between ZrO2 ceramic and 316 stainless steel brazed using Ag–Cu–In–Ti filler

An active Ag-based filler containing the melting point depressant of In was used for brazing ZrO2 ceramic with 316 stainless steel (SS) at relatively low brazing temperatures. The brazing feasibility to obtain a robust joint was investigated via changing brazing temperatures from 740 to 820 °C with a holding time of 10–30 min. The typical microstructure of the ZrO2/316SS joint was ZrO2/TiO/Cu2Ti4O + Ag(s, s) + Cu(s, s)/Ag(s, s) + Cu(s, s) + Cu(Ti, In) + FeTi + Cu(Ti, Fe)/316SS. The type of reaction products primarily depended on the brazing temperature, and the TiO phase appeared only at 780 and 800 °C, while the FeTi formed at temperatures higher than 760 °C. Meanwhile, the blocky Cu(Ti, In) and Cu(Ti, Fe) compounds were gradually replaced by the FeTi phase due to the enhanced affinity of Ti and Fe in the liquid alloy. The maximum shear strength reached 308 MPa at 780°C-20 min, and the typical fracture occurred at the Ag-based solid solution and reaction bilayer bordering the ZrO2 ceramic. Notably, a shear strength of above 270 MPa was obtained at wide temperatures from 760 to 820 °C, higher than ZrO2/SS brazed joints using other Ag-based fillers.

Efficiency enhancement and chrono-photoelectron generation in dye-sensitized solar cells based on spin-coated TiO2 nanoparticle multilayer photoanodes and a ternary iodide gel polymer electrolyte

The effect of the thickness of a multilayer TiO2 photoanode on the performance of a dye-sensitized solar cell (DSC) made with a polyethylene oxide-based gel polymer electrolyte containing ternary iodides and performance enhancer 4-tert-butylpyridine is studied. Multilayer photoanodes consisting of up to seven layers of TiO2 nano-particles (13 nm and 21 nm) are prepared by spin coating of successive layers. XRD results confirm the predominant presence of the anatase phase of TiO2 in the multilayer structure after sintering. The SEM images reveal the formation of a single TiO2 film upon sintering due to merging of individually deposited layers. The photocurrent density (JSC) and the efficiency increase with the number of TiO2 layers exhibiting the maximum efficiency and JSC of 5.5% and 12.5 mA cm−2, respectively, for the 5-layered electrode of total thickness 4.0 µm with a 9.66 × 10–8 mol cm−2 surface dye concentration. The present study introduces a method of determining the rate of effective photoelectron generation and the average time gap between two successive photon absorptions where the respective results are 1.34 molecule−1 s−1 and 0.74 s for the most efficient cell studied in this work.

Zinc ion exchange assisted synthesis of R-TiO2@C hollow spheres with superior lithium-ion storage performance

Nanostructured anode materials hold the key to advance the performance of the corresponding lithium-ion batteries as advanced electrochemical energy storage devices. Here, we designed a zinc exchange assisted phase change strategy as an acid-free and well-controlled approach to successfully synthesize a kind of rutile phase TiO2 @C (R-TiO2 @C) hollow spheres with well-defined size by using SiO2 spheres as sacrificial templates. The exchanged zinc ions in an alcohol solvothermal reaction were considered as a phase transition medium to promote the formation of a high-quality rutile TiO2 crystal through a high temperature solid-state heat way. By this way, the final morphologies of rutile phase TiO2 nanocrystals were well controlled, and the rutile TiO2 phase transformation temperature was lower than that of conventional one-step high temperature calcination way (without zinc ions exchange). Note that it successfully avoided using acids as mediums to promote the formation of rutile phase TiO2 crystal in the nano process. Meanwhile, the carbon layer formed by a hydrothermal carbonization reaction not only provided self-supporting solid-state in situ reducing medium for Zn2+ to Zn vapor but also produced conductive porous carbon coating porous and robust R-TiO2 spherical shell with nanosized subunits. The reaction process and mechanism of zinc ions induced phase transformation were discussed. Benefiting from the nanoscale morphology-regulation and hollow structure with enhanced ability of ion and electron transfer as well as electrolyte transport, the resultant R-TiO2 @C hollow spheres can significantly promote Li ions storage and deliver a high reversible specific capacity of 115.6 mAh g-1 at 5.0 C over 1600 cycles. A typical electrochemical reaction on Li ions inserted into TiO2 crystal was simply elaborated as well. This work demonstrates its great potential for practical application in lithium-ion batteries.

LVOF sprayed Ti-HAp composite coatings for internal fixation devices in orthopaedic applications

Pure hydroxyapatite, pure titanium, Ti60-HAp (60%Ti), and Ti40-HAp (40%Ti) composite coatings were deposited on 254 SMO steel by Low-Velocity Oxy-fuel (LVOF) spraying. Among the various LVOF sprayed coatings, the Ti40-HAp coating has the highest microhardness and adhesion strength values attributed to its low porosity and low coefficient of thermal expansion. The potentiodynamic polarisation and electrochemical impedance spectroscopy tests also indicated a lower corrosion rate for Ti40-HAp coating in simulated body fluid (SBF). The bacterial adhesion has shown a direct relationship with the surface roughness of the coatings. The bioactivity of the Ti-HAp composite coating was established through an in-vitro bioactivity test. The bioactivity decreased with increasing Ti content in the coating. The formation of rutile TiO2 and CaTiO3 phases significantly enhanced the microhardness, adhesion strength and corrosion resistance.

Independent and simultaneous photocatalytic decontamination and disinfection of water over In2O3/TiO2 heterojunctions

We have explored the application of In2O3/TiO2 heterojunctions to the photocatalytic removal of a substance classified as a pollutant of emerging concern, such as the anti-inflammatory drug sodium diclofenac (DCF), from aqueous solutions. In addition, the study of water disinfection by means of photocatalysis, simultaneously with the elimination of DCF, has been carried out with the same catalysts, by using bacterial populations of the genus Enterococcus faecalis. The In2O3/TiO2 catalysts with different indium amounts consist of bi-phasic samples with anatase TiO2 and In2O3 phases, without evidence in In doping into the titania structure, and show, according to UV–vis and time-resolved fluorescence spectra, light absorption into the visible range and interfacial charge transfer from the conduction band of In2O3 to that of TiO2. Complete photocatalytic removal of DCF was achieved by using all catalysts after 120 min of irradiation, being the most active the catalyst with 5% of In2O3, in agreement with its highest efficiency of interfacial charge transfer revealed by fluorescence lifetime. In contrast, in terms of DCF mineralization, the 5In2O3/TiO2 catalyst did not outperform the pristine TiO2, the higher mineralization percentage being achieved with 1% In. Simultaneous decontamination and disinfection experiments show that the 5% In2O3/TiO2 heterojunction outperforms the activity of titania for DFC removal in the presence of Enterococcus faecalis, but not for the inactivation of bacteria.

Synthesis of Tio2 photocatalyst with tunable optical properties and exposed facet for textile wastewater treatment

TiO2 semiconductor plays a paramount important as an active photocatalyst mainly due to its photo-induced electron transfer properties. The metastable anatase in particular are widely accepted to have the most photoactive activity in catalytic application as opposed to rutile TiO2. This is majorly due to the significantly lower recombination rate of electron pair possesses by anatase TiO2. Unfortunately, high recombination rate in anatase TiO2 hinders its application as a functional photocatalyst. Therefore, it is crucial to further enhance the photocatalytic activity of anatase TiO2, by modifying its optical properties, morphological properties, and crystal facet. The study aims to provide a benign synthesis method for TiO2 with a co-exposed {001}/{100} anatase TiO2 facet. The synthesis was conducted via one-pot reflux condensation method. A concise evaluation upon the effect of different synthesis heating duration, temperature and doping materials towards the crystal phase, morphology, and photocatalytic performance of TiO2 were conducted. Anatase TiO2 with high percentage of the high-energy {001} facet have the ability to boost the adsorption and photocatalytic performance as opposed to anatase TiO2 dominated with a thermodynamically stable {101} facet. The incorporation of non-metal dopant (HF) acts as surface modifier which leads to the enhancement of {001} facet percentage. This study further evaluates the functionalities of HCl in paving way towards the formation of mid-gap state, hence improving Anatase TiO2 optical properties. The reduction of band gap of the anatase TiO2 can clearly be identified from the shifts in the adsorption band towards higher wavelength. From the findings, it was found that the synergistic effect upon co-doping anatase TiO2 with the two non-metal dopants plays an important role in altering the ratio of exposed facet hence leading towards improving the photocatalytic efficiency of the nanomaterial. To evaluate the photocatalytic performance of the synthesized TiO2, Remazol Brilliant Blue (0.01 g/L) was chosen as the target pollutant. The enhanced photodegradation of co-doped F/Cl-TiO2 was evaluated and it was found that 87.21% and 43.21% of Remazol Brilliant Blue had successfully been degraded within 120 min with irradiation of broad spectrum and blue light (475 nm) respectively. This is mainly attributed to the co-exposed {001}/{100} anatase TiO2 facet presence in the F/Cl-TiO2 sample.

Photocatalytic decomposition of Congo red dye by black paste@TiO2 as an efficient recyclable photocatalyst

Abstract Manufacturing active and economical catalysts and using them in water treatment is one of the most important challenges facing researchers. Spent batteries signify a source of harmful materials when discarded without suitable treatment. In this work, a black paste as one of the main components of spent battery doped with different ratios of TiO2 nanocomposites (0, 1, 3, 7, and 10 %) were manufactured using the sol–gel method. The characterization of the paste@TiO2 nanocomposites has been investigated by SEM, XRD, DRS, FTIR, and BET analysis. The results show formation of anatase phase of TiO2 in all doped samples. While the XRD of black paste indicates the presence of Mn3O4 as a main phase. Photocatalytic properties of black paste@TiO2 nanocomposites have been investigated using Congo red dye. The results showed that the presence of TiO2 in the paste could increase the specific surface area and the composites’ photocatalytic efficiency. A higher percentage of TiO2 (10 %) added to the black paste resulted in higher black paste@TiO2 nanocomposite catalytic activity. The experimental photodegradation data were found to be consistent with the Lagergren kinetics model. The recyclability of the photocatalysts was examined for reuse in the industrial sector. Signifying that the black paste dopped with 10 % of TiO2 (PTO4) photocatalyst in this study had high reusability.

Quantification of titanium dioxide (TiO2) anatase and rutile polymorphs in binary mixtures by Raman spectroscopy: an interlaboratory comparison

This article presents an interlaboratory comparison (ILC) on Raman spectroscopy as a technique for relative quantification of the two most common polymorphs of titanium dioxide (TiO2)—anatase and rutile—in binary mixtures. Some standard methods are currently employed internationally for the determination of TiO2 content in samples (ISO 591-1, ASTM D3720-90), but require extensive sample preparation, do not distinguish between the two polymorphs or are accurate only for small fractions of either polymorph. Raman spectroscopy is a well-suited characterization technique for measuring and differentiating TiO2 in a fast, non-invasive way, while requiring no particular reagent or sample preparation. Eleven international participants conducted the study under the framework of Versailles Project on Advanced Materials and Standards. The collected data was analyzed by means of partial least squares regression after spectral preprocessing. The resulting models all show discrepancies of lower than 2% from the nominal values in the quantitative analysis over the concentration range of 5%–95% mixture fractions, with many datasets showing substantial improvement margins on this figure. The results of this ILC provide validation of Raman spectroscopy as a reliable method for quantification of TiO2 phases.

TiO2 Nanotubes Decorated with Mo2C for Enhanced Photoelectrochemical Water-Splitting Properties.

The presence of Ti3+ in the structure of TiO2 nanotube arrays (NTs) has been shown to enhance the photoelectrochemical (PEC) water-splitting performance of these NTs, leading to improved results compared to pristine anatase TiO2 NTs. To further improve the properties related to PEC performance, we successfully produced TiO2 NTs using a two-step electrochemical anodization technique, followed by annealing at a temperature of 450 °C. Subsequently, Mo2C was decorated onto the NTs by dip coating them with precursors at varying concentrations and times. The presence of anatase TiO2 and Ti3O5 phases within the TiO2 NTs was confirmed through X-ray diffraction (XRD) analysis. The TiO2 NTs that were decorated with Mo2C demonstrated a photocurrent density of approximately 1.4 mA cm-2, a value that is approximately five times greater than the photocurrent density exhibited by the bare TiO2 NTs, which was approximately 0.21 mA cm-2. The observed increase in photocurrent density can be ascribed to the incorporation of Mo2C as a cocatalyst, which significantly enhances the photocatalytic characteristics of the TiO2 NTs. The successful deposition of Mo2C onto the TiO2 NTs was further corroborated by the characterization techniques utilized. The utilization of field emission scanning electron microscopy (FESEM) allowed for the observation of Mo2C particles on the surface of TiO2 NTs. To validate the composition and optical characteristics of the decorated NTs, X-ray photoelectron spectroscopy (XPS) and UV absorbance analysis were performed. This study introduces a potentially effective method for developing efficient photoelectrodes based on TiO2 for environmentally sustainable hydrogen production through the use of photoelectrochemical water-splitting devices. The utilization of Mo2C as a cocatalyst on TiO2 NTs presents opportunities for the advancement of effective and environmentally friendly photoelectrochemical (PEC) systems.

Tailoring performance of hybrid supercapacitors by fluorine-rich block copolymer-derived carbon coated mixed-phase TiO2 nanoparticles

Hybrid supercapacitors can function as both batteries and supercapacitors owing to their high specific energy and capacitive power, respectively. Transition metal oxide-based electrodes exhibit a high theoretical specific capacitance, but their large-scale application in charge storage devices is limited by their low conductivity and electrical stability. To address this problem, we introduced a highly conductive carbon coating over mixed-phase titanium dioxide (C/TiO2) using a novel carbon-rich polyacrylonitrile block copolymer containing an active pentafluorophenyl acrylate ester block (PAN-b-PFPA). The LiFePO4 (LFP) positrode and C/TiO2 negatrode assembled hybrid LFP║C/TiO2 @ 800 supercapacitor exhibited a high specific capacitance of 227 F/g (current density of 1 A/g), power density of 500 W/kg, and energy density of 32 W h/kg. Importantly, higher specific capacitance (∼84%) and Coulombic efficiency (∼96%) were maintained over 5000 charge–discharge cycles. The improved performance of hybrid LFP║C/TiO2 @ 800 supercapacitor is attributable to (1) selectively mixed anatase–rutile TiO2 phases that led to additional Ti3+ oxidation state formation, (2) firm porous carbon coating resulting from the surface anchoring of PAN-b-PFPA copolymer, and (3) fluorine/sulfur impurities from pyrolysis residues. The carbon coating of transition metal oxides from the pyrolysis of PAN-b-PFPA copolymers can facilitate the large-scale development of energy storage materials.

In2S3@TiO2/In2S3 Z-Scheme Heterojunction with Synergistic Effect for Enhanced Photocathodic Protection of Steel.

In this work, a TiO2/In2S3 heterojunction film was successfully synthesized using a one-step hydrothermal method and applied in the photocathodic protection (PCP) of 304SS. The octahedral In2S3 and In2S3@TiO2 nanoparticles combined and coexisted with each other, with In2S3 quantum dots growing on the surface of TiO2 to form In2S3@TiO2 with a wrapping structure. The composite photoelectrode, which includes TiO2 with a mixed crystalline phase and In2S3, exhibited significantly enhanced PCP performance for 304SS compared with pure In2S3 and TiO2. The In2S3@TiO2/In2S3 composites with 0.3 g of P25 titanium dioxide (P25) showed the best protection performance, resulting in a cathodic shift of its OCP coupled with 304SS to -0.664 VAgCl. The electron transfer tracking results demonstrate that In2S3@TiO2/In2S3 forms a Z-scheme heterojunction structure. The enhanced PCP performance could be attributed to the synergistic effect of the mixed crystalline phase and the Z-scheme heterojunction system. The mixed crystalline phase of TiO2 provides more electrons, and these electrons are gathered at higher energy potentials in the Z-scheme system. Additionally, the built-in electric field further promotes the more effective electrons transfer from photoelectrode to the protected metals, thus, leading to enhanced photoelectrochemical cathodic protection of 304SS.

Mechanical, antibacterial and cytotoxic characteristics of nanolayered TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings

Titanium and titanium alloy materials are often made as medical implants. Surface properties of titanium medical implants play decisive roles for antibacterial and biological response and tissue biocompatibility. In this study, cathode arc evaporation (CAE) technology was used to deposit TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings with nanostructures on the Ti–6Al–4V dental abutment screws. The deposited coatings were then oxidized at high temperature to produce different oxides on the surface of the coatings. The mechanical properties, antibacterial properties and biocompatibilities of the coatings were analyzed. The effect of coatings on the abutment screw loosening and removal torque between the abutment screw and the pure titanium implant fixture was studied by removal torque measurement. In addition, Staphylococcus aureus (S. aureus) was used for evaluating the antibacterial properties of coatings, and mouse fibroblasts (L929) were used for ISO 10993-5 cytotoxicity analyses to determine whether it had good biocompatibility.Nanolayered structures and multiphases of polycrystalline TiNb–Zr–Ta were obtained by co-deposition of Ta, Zr and TiNb. When small content of N was introduced, the TiNb–Zr–Ta(N) showed a polycrystalline TiNb–Zr–Ta where N atoms entered the metallic lattice at interstitial sites. After oxidation, oxide phases of Ta2O5, TiO2, Nb2O5 and ZrO2 were formed on the surface of TiNb–Zr–Ta and TiNb–Zr–Ta(N). Ta2O5 was obtained on the surface of the coating prior to other oxides such as TiO2, Nb2O5 and ZrO2. The deposited TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had high contact angle and exhibited a hydrophobic feature, while the annealed TiNb–Zr–Ta–O and TiNb–Zr–Ta(N)–O showed hydrophilicity. The deposited TiNb–Zr–Ta had similar hardness and Young's modulus values to that of the uncoated Ti–6Al–4V. When N was doped, the TiNb–Zr–Ta(N) had the highest hardness and Young's modulus. The hardness of the annealed TiNb–Zr–Ta(N) coating only decreased slightly due to the small oxide layer of ∼140 nm. Compared with the uncoated Ti–6Al–4V, TiNb–Zr–Ta serial coatings deposited on abutment screws had higher removal torques, which prevented the abutment screw of dental implant from loosening after long-term use. The biocompatibility of TiNb–Zr–Ta serial coatings was similar to that of the uncoated Ti–6Al–4V. In addition, the oxidized TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had excellent antibacterial properties. It is speculated that the resulting Ta2O5 of both coatings may inhibit bacterial growth and improve the antibacterial effect. Based on the above advantages, the TiNb–Zr–Ta serial coatings are expected to have the potential to be applied to biomedical implants.