Titanate Nanotubes Research Articles

Synthesis, characterization of vanadium-doped titanate nanotubes nanocatalysts towards degradation of methyl orange, bacteria, and fungus

Synthesis, characterization of vanadium-doped titanate nanotubes nanocatalysts towards degradation of methyl orange, bacteria, and fungus

The application of carboxylic acids on the surface of titanate nanotubes for further functionalization

The application of carboxylic acids on the surface of titanate nanotubes for further functionalization

Titanate nanotubes modified with gallium and cerium and their cytotoxic activity

Titanate nanotubes modified with gallium and cerium and their cytotoxic activity

Improved thermal, dielectric, and mechanical properties of acrylate composites with diethylene glycol and silane-treated ternary hybrid fillers via three-dimensional vat photopolymerization

Rapid advances in electronic devices have led to the production of highly integrated structures, which are prone to the thermal accumulation problem. Accordingly, polymer-based composites have been introduced to solve the thermal dissipation problem and endow energy storage properties. In this study, an acrylate polymer-based composite with boron nitride (BN), barium titanate (BT), and carbon nanotubes (CNTs) ternary fillers was fabricated via three-dimensional (3D) vat photopolymerization (VPP). To improve the processability of the printing, diethylene glycol (DEG) was added as a viscosity reducer, and ternary fillers were surface-treated with silane functional groups. The surface-treated ternary composite improved tensile strength, thermal conductivity, and dielectric constant compared to a composite composed of raw ternary fillers. Furthermore, the composites with silane-treated BN and CNTs showed thermal conductivity of 2.796 W/(m∙K) and thermal conductivity enhancement of 1153% compared to the acrylate matrix. The dielectric constants and electrical insulation of the composites were also investigated. The proposed method ushers a new era in polymer-based composites with improved thermal conductivity and energy storage properties as well as desired and controlled complex structures through swift and sophisticated 3D VPP printing.

Ultra-wide bandwidth electromagnetic wave and enhanced microwave absorption of Cu0.5Ni0.5Fe1.9Mn0.1O4 @CaTiO3 @MWCNTs nanocomposite in X-band frequency

Broad bandwidth electromagnetic (EM) wave absorbers are persistently desired due to their massive applications in many fields. This paper reports the development of ultra-wide bandwidth microwaves, with the enhanced microwave absorption of thin-thickness absorbers. The design of RAMs requires a structure composed of magnetic-dielectric elements, meta-materials, and large impedance matching. This paper highlights the strategic approach to obtain the ultrawide, thin, and high impedance matching of the absorber. The Spinel-ferrite Cu0.5Ni0.5Fe1.9Mn0.1O4 (SF), Spinel ferrite doped calcium titanium oxide, Cu0.5Ni0.5Fe1.9Mn0.1O4@CTO (SF@CTO), and Spinel ferrite doped calcium‑copper titanate and multiwalled carbon nanotubes Cu0.5Ni0.5Fe1.9Mn0.1O4@CaTiO3@MWCNT (SF@CTO@MWCNT) nanocomposites absorbers were reported. The spinel ferrite and calcium copper titanite were synthesized via a co-precipitation method, and hydrothermally with the MWCNT by acid functionalization process. The effectiveness of microwave absorbing the samples was measured using a vector network analyzer with sample thicknesses of 1.0 mm, 2.0 mm, and 3.0 mm, in the frequency range of 8.0 to 12.0 GHz. The highest reflection loss (RL) of −33.3 dB at 9.6 GHz was anticipated using the complex permittivity and permeability characteristics. Interfacial electric polarisation, electromagnetic impedance matching, as well as the numerous scattering network structure of SF@CTO@MWCNT nanocomposites, are all credited with effective ultra-wide bandwidth microwave absorption. This report is important for paving future work in obtaining a desired thin and ultra-wide bandwidth absorber.

Structural phases of sodium titanate nanotubes obtained in different synthesis conditions: A theoretical study

Structural phases of sodium titanate nanotubes obtained in different synthesis conditions: A theoretical study

Hydrothermal Synthesis of a Technical Lignin-Based Nanotube for the Efficient and Selective Removal of Cr(VI) from Aqueous Solution.

Aminated lignin (AL) was obtained by modifying technical lignin (TL) with the Mannich reaction, and aminated lignin-based titanate nanotubes (AL-TiNTs) were successfully prepared based on the AL by a facile hydrothermal synthesis method. The characterization of AL-TiNTs showed that a Ti-O bond was introduced into the AL, and the layered and nanotubular structure was formed in the fabrication of the nanotubes. Results showed that the specific surface area increased significantly from 5.9 m2/g (TL) to 188.51 m2/g (AL-TiNTs), indicating the successful modification of TL. The AL-TiNTs quickly adsorbed 86.22% of Cr(VI) in 10 min, with 99.80% removal efficiency after equilibration. Under visible light, AL-TiNTs adsorbed and reduced Cr(VI) in one step, the Cr(III) production rate was 29.76%, and the amount of total chromium (Cr) removal by AL-TiNTs was 90.0 mg/g. AL-TiNTs showed excellent adsorption capacities of Zn2+ (63.78 mg/g), Cd2+ (59.20 mg/g), and Cu2+ (66.35 mg/g). After four cycles, the adsorption capacity of AL-TiNTs still exceeded 40 mg/g. AL-TiNTs showed a high Cr(VI) removal efficiency of 95.86% in simulated wastewater, suggesting a promising practical application in heavy metal removal from wastewater.

Glycerol carbonate synthesis over nanostructured titanate catalysts: Effect of morphology and structure of catalyst

The indirect conversion of CO2 into glycerol carbonate using DMC was investigated using pristine sodium titanate nanotubes (NaTNT) and nanostructured titanates (calcined NaTNT at different temperatures) as catalysts. The calcination changes the morphology of the nanostructured titanates, between 200 and 400 °C the nanotubes shape is retained, however above these temperatures (500 and 600 °C) nanoribbons were identified, as well as nanorods obtained at 700 °C. A significant decrease in specific surface area and total pore size in temperatures up 500 °C was also observed. Furthermore, a decrease in the Ti+4/Ti+2 ratio and in the binding energy of Ti 2p3/2 and Ti 2p1/2 were observed, indicating an increase in the electron density and consequently increase in the Lewis acidity character of the titanium atom. All the nanostructured titanates showed good catalytic activity with glycerol conversion and GC selectivity above 90%. The results of the recycling showed that the nanostructured catalysts retained a good catalytic activity with high glycerol conversion (> 90%) although the GC selectivity decreased due the formation of glycidol, a high value-added by-product.

Photoelectrochemical degradation of TMAH by green synthesized silver modified titanate nanotube arrays

In this study, titanate nanotube arrays (TNAs) were prepared by using electrochemical anodization, and the silver nanoparticles were deposited on a titanate dioxide nanotube array (Ag/TNAs) by green synthesis methods. The Ag/TNAs was further applied to degrade tetramethylammonium hydroxide (TMAH) in a photoelectrochemical (PEC) system. SEM results showed that the diameter and length were 121.7 nm and about 3.45 µm, respectively, for TNAs. The deposited silver nanoparticles showed spherical and flaky shapes depending on using tea and coffee as green reducing agents, respectively. XPS showed that the atomic percentage of silver in Ag/TNAs-CTC5 and Ag/TNAs-CGA2.5 was 6.60% and 1.76%, individually. Results of UV–vis analyses indicated that the absorbance edge of TNAs red-shifts to a more extended wavelength region after silver modification. The photocurrents of Ag/TNAs-CTC5 (5.03 mA/cm2) and Ag/TNAs-CGA2.5 (3.63 mA/cm2) were 51% and 32% higher than that of TNAs (2.45 mA/cm2), illustrating that the photocatalytic ability of TNAs was significantly enhanced after silver nanoparticles modifying. Electrochemical impedance analysis (EIS) results confirmed that the electron lifetime of Ag/TNA-CTC and Ag/TNAs-CGA was 6.6 and 1.82 times longer than that of the TNA in the PEC system. Mott-Schottky analyses indicated that TNAs, Ag/TNAs-CTC5, and Ag/TNAs-CGA2.5 are n-type semiconductors with a density of dopants of 3.16 × 1019, 1.42 × 1020, and 9.49 × 1019 cm−3. The results of TMAH degradation showed that Ag/TNAs-CTC5 performed the highest efficiency at pH= 3 in the PEC system. EPR analyses of TNAs and Ag/TNAs-CTC5 showed a peak intensity of 1:2:2:1 which represented the characteristic DMPO−OH, revealing the dominant oxidants of the PEC system.

Adsorption Behavior of U(VI) and Re(VII) on Iron Sulfide Nanoparticles Modified with Titanate Nanotubes: Mechanism and Performance Insights

AbstractA novel nanocomposite (TNTs‐FeS) was developed by anchoring ferrous sulfide (FeS) nanoparticles immobilized on titanate nanotubes (TNTs) by hydrothermal method to remove U(VI) and Re(VII) from aqueous solution, and the removal mechanism and efficiency were examined. The experimental results showed that the TNTs can effectively improve the dispersibility and stability of FeS. The environmental conditions, including initial solution pH, initial concentration, equilibrium time, and dosage, played an important role in the remediation process, which can affect the immobilization efficiency significantly. The maximum quantity removal of U(VI) and Re(VII) was 291.67 and 226.23 mg/g at pH of 6.0 and 12.0. The adsorption kinetics and the equilibrium isotherms of U(VI) and Re(VII) all fitted well with the pseudo‐second‐order model (R2>0.99) and the Freundlich model (R2>0.99). The main mechanism of removal by TNTs‐FeS was electrostatic attraction, chemical reduction, and surface complexation. Thus, TNTs‐FeS composites exhibited a high potential to remove U(VI) and Re(VII) heavy metal ions from the surface and groundwater.

Simultaneous removal of Cd(II) and 2-chlorophenol from aqueous solution using activated carbon supported titanate nanotubes

Combined heavy metals and chlorinated organic compounds have been widely reported in industrial wastewater. Yet, simultaneous removal of these contaminants remains challenging. In this study, a bi-functional composite (TNTs@AC) was prepared based on commercial titanium dioxide (TiO2) and activated carbon (AC) and tested for simultaneous removal of Cd(II) and 2-chlorophenol (2-CP). Under the action of high temperature and pressure, TiO2 was transformed into titanate nanotubes (TNTs) and bound to AC, and in the meanwhile, nanoscale AC particles were patched on the TNTs. In the mixed TNTs and AC phases, TNTs was responsible for taking up Cd(II), whereas AC for 2-CP. As such, the relative adsorption capacities of the composite for Cd(II) and 2-CP varied with the mass ratio of TiO2:AC, with decent uptakes for both chemicals in the mass ratio rage of 1:3 ∼1:1. TNTs@AC (prepared at TiO2:AC = 1:1) demonstrated fast sorption kinetics and high sorption capacities for both Cd(II) and 2-CP, with a maximum Langmuir adsorption capacity of 109 and 52 mg/g, respectively, in the single solute systems. In the binary systems, the adsorption capacity of Cd(II) was not affected by the presence of 2-CP, whereas the presence of Cd(II) slightly increased the uptake of 2-CP in the low Cd concentration domain (final Cd < 7 mg/L) but mildly inhibited the uptake at Cd > 7 mg/L. The dominant adsorption mechanism of Cd(II) was ion exchange between Cd(II) and Na+/H+ of the -ONa/H group of TNTs; while AC served as the primary sink for 2-CP via hydrophobic interaction along with some other possible mechanisms such as surface complexation and hole filling. TNTs@AC also performed well under common environmental conditions (pH, common co-ions, and dissolved organic matter). The formation of mixed TNTs and AC microphases appears promising for simultaneous removal of heavy metals and organic compounds from contaminated water.

Reactive species regulation by interlayered Na+/H+ of titanate nanotubes decorated Co(OH)2 hollow microsphere for peroxymonosulfate activation and gatifloxacin degradation

Emerging organic pollutants (EOPs) in water are of great concern due to their high environmental risk, so urgent technologies are needed for effective removal of those pollutants. Herein, a heterogeneous advanced oxidation process (AOP) of peroxymonosulfate (PMS) activation by functional material was developed for degradation of a typical antibiotic, gatifloxacin (GAT). The reactive species including sulfate radical (SO4•−) and singlet oxygen (1O2) in this AOP were regulated by interlayered ions (Na+/H+) of titanate nanotubes that supported on Co(OH)2 hollow microsphere. Both the Na-type (NaTi-CoHS) and H-type (HTi-CoHS) materials achieved efficient PMS activation for GAT degradation, and HTi-CoHS even exhibited a relatively high degradation efficiency of 96.6% within 5 min. Co(OH)2 was considered the key component for generation of SO4•− after PMS activation, while hydrogen titanate nanotubes (H-TNTs) promoted the transformation of peroxysulfate radical (SO5•−) to 1O2 by hydrogen bond interaction. Therefore, when the interlayer ion of TNTs transformed from Na+ to H+, more 1O2 was produced for organic pollutant degradation. H-TNTs with lower symmetry preferred to adsorb PMS molecules to achieve interlayer electron transport through hydrogen bonding, rather than electrostatic interaction of Na+ for Na-TNTs. In addition, the degradation pathway of GAT mainly proceeded by the cleavage of C–N bond at the 8 N site of the piperazine ring, which was confirmed by condensed Fukui index and mass spectrographic analysis. This work gives new sights into the regulation of reactive species in AOPs by the composition of material and promotes the understanding of pollutant degradation mechanisms in water treatment process.

The structural, optical and electrical properties of sodium titanate nanotubes sensitized with nitrogen/sulfur co-doped graphene quantum dots as potential materials for quantum dots sensitized solar cells

The structural, optical and electrical properties of sodium titanate nanotubes sensitized with nitrogen/sulfur co-doped graphene quantum dots as potential materials for quantum dots sensitized solar cells

Application of CdTe quantum dots sensitized titanate nanotubes in photocatalytic degradation of organic pollutants under visible light irradiation

The use of solar-driven photocatalysis for the degradation of recalcitrant organic waste from water is a promising and environmentally friendly technology to meet the challenge of mitigating increasing global pollution. This paper presents a new composite of layered H2Ti3O7 hydrothermal nanotubes (TNT) with cadmium telluride quantum dots prepared by the simple mixing suspensions of both components in TNT/CdTe-QDs ratios in the range of 1:0.005–1:0.03. The products were characterized by X-ray diffraction, spectroscopic techniques such as Fourier transform infrared, Raman scattering, UV–visible diffuse reflectance, photoluminescence, and X-ray photoelectron spectroscopy, as well as by scanning and transmission electron microscopy. The photocatalytic performance of the products was tested by photocatalytic degradation of two molecular models of contaminants, methyl orange (MO) and 4-chlorophenol (4-CP). Nearly 100 % removal of organic contaminants was achieved and the degradation rate of MO and 4-CP under simulated sunlight in the presence of QDs was approximately five and four times faster than using TNT alone, respectively. The degradation rate response in the presence of specific radical scavengers corresponds to a direct Z-scheme photocatalysis. Recycling experiments demonstrated a structurally stable catalyst that maintains its efficiency after five irradiation cycles. Photoelectrochemical and photocurrent measurements validated the synergistic effect observed, reflecting that heterojunction promotes the transfer of photogenerated electrons and holes, decreasing recombination changes and improving photocatalytic activity.

Exploring the Antimicrobial Activity of Sodium Titanate Nanotube Biomaterials in Combating Bone Infections: An In Vitro and In Vivo Study.

The majority of bone and joint infections are caused by Gram-positive organisms, specifically staphylococci. Additionally, gram-negative organisms such as E. coli can infect various organs through infected wounds. Fungal arthritis is a rare condition, with examples including Mucormycosis (Mucor rhizopus). These infections are difficult to treat, making the use of novel antibacterial materials for bone diseases crucial. Sodium titanate nanotubes (NaTNTs) were synthesized using the hydrothermal method and characterized using a Field Emission Scanning Electron Microscope (FESEM), High-Resolution Transmission Electron Microscope (HRTEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and Zeta sizer. The antibacterial and antifungal activity of the NaTNT framework nanostructure was evaluated using Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Disc Diffusion assays for bacterial activity, and Minimum Fungicidal Concentration (MFC) for antifungal investigation. In addition to examining in vivo antibacterial activity in rats through wound induction and infection, pathogen counts and histological examinations were also conducted. In vitro and in vivo tests revealed that NaTNT has substantial antifungal and antibacterial effects on various bone-infected pathogens. In conclusion, current research indicates that NaTNT is an efficient antibacterial agent against a variety of microbial pathogenic bone diseases.

Effect of Hydrothermal and Vapor Thermal Treatments on Apatite Inductivity of Titanate Nanotubes on Anodized Ti-5Nb-5Mo Surface.

Although titanium (Ti) alloys have been widely employed as biomedical materials, they cannot achieve satisfactory osseointegration when implanted in the human body due to their biologically inert nature. Surface modification can enhance both their bioactivity and corrosion resistance. The present study employed a Ti-5Nb-5Mo alloy with a metastable α″ phase. This alloy may undergo phase changes after conventional high-temperature heat treatment, which can deteriorate its properties. This study heat-treated the anodized Ti-5Nb-5Mo alloy by using a low-temperature hydrothermal or vapor thermal method to analyze the effects of heat treatment on its apatite induction. The results revealed that the porous nanotube structure on the surface of the alloy was transformed into anatase nanoparticles after hydrothermal or vapor thermal treatment at 150 °C for 6 h. After immersion in simulated body fluid (SBF) for 7 days, the amount of apatite deposited on the surface of the vapor thermal-treated alloy exceeded that on the hydrothermal-treated alloy. Therefore, post-heat treatment of anodized Ti-5Nb-5Mo by using the vapor thermal method can enhance its apatite inductivity without altering its structure.

Synthesis, characterization, and thermal stability study of sodium and sodium–aluminum titanate nanotubes

Synthesis, characterization, and thermal stability study of sodium and sodium–aluminum titanate nanotubes

Preparation and Ferroelectric Properties of Ba(1-x-y)CaxSryTiO3 Nanotubes

In this paper, Ba(1-x-y)CaxSryTiO3 nanotubes with different doping concentrations were prepared by hydrothermal synthesis, and then their micro morphology, crystal structure, and ferroelectric properties were analyzed by SU8010 scanning electron microscope, D/MAX-2500 X-ray diffraction tester, and TF2000. It is found that the barium titanate nanotubes co doped with Ca and Sr have obvious tubular structure. With the increase of doping concentration, the nanotube diameter becomes smaller, the tube wall becomes thicker, and the ferroelectric properties of the samples increase first and then decrease. When 0.002mol/L Ca(CH3COO)2 and 0.002mol/L Sr(CH3COO)2 are doped, the maximum residual polarization intensity of Ba(1-x-y)CaxSryTiO3 is 0.097µC/cm2. At this time, there is a clear hysteresis loop image, and the ferroelectric performance is the best.

Direct hydrothermal synthesis of Titanate Nanotubes with high selectivity for oxidative desulfurization

Direct hydrothermal synthesis of Titanate Nanotubes with high selectivity for oxidative desulfurization

Self-Seeding Synthesis of Hierarchically Branched Rutile TiO2 for High-Efficiency Dye-Sensitized Solar Cells.

This study presents a unique and straightforward room temperature-based wet-chemical technique for the self-seeding preparation of three-dimensional (3D) hierarchically branched rutile TiO2, abbreviated HTs, employing titanate nanotubes as the precursor. In the course of the synthesis, spindle-like rutile TiO2 and the intermediate anatase phase were first obtained through a dissolution/precipitation/recrystallization process, with the former serving as the substrates and the latter as the nucleation precursor to growing the branches, which finally gave birth to the production of 3D HTs nanostructures. When the specifically created hierarchical TiO2 was used as the photoanode in dye-sensitized solar cells (DSCs), a significantly improved power conversion efficiency (PCE) of 8.32% was achieved, outperforming a typical TiO2 (P25) nanoparticle-based reference cell (η = 5.97%) under the same film thickness. The effective combination of robust light scattering, substantial dye loading, and fast electron transport for the HTs nanostructures is responsible for the remarkable performance.