TiO2 NTAs Research Articles

Enhancing Electrochemical Cells Performance with Modified Ionic Liquids and Deep Eutectic Solvents using Titanium Dioxide Nanoelectrodes- Graphite

Ionic liquids (ILs) and deep eutectic solvents (DESs) have been found to be highly effective as electrolytes in TiO2 NTAs-graphite cells when combined with additives that enhance conductivity by reducing the viscosity of these liquids. The presence of CaCl2.6H2O: Acetamide DES with DI water as an additive resulted in a cell voltage of 1.31V and an internal resistance of 19 ohm. This can be attributed to the concentration and quality of the ionic species. The cells exhibited an interesting response to the AlCl3-chloroacetamide IL with dichloromethane DCM as an additive, with a cell voltage of 1.81V and an internal resistance of 5.0 ohm. Once again, this is influenced by the quality and concentration of the ionic species. Furthermore, the cells demonstrated thermal stability during the charging and discharging processes. Additionally, the surfaces of the TiO2 NTAs electrodes were examined, along with the impact of the IL and DES on these electrodes, using SEM and EDXA equipment.

Anodic Synthesis of Highly Ordered TiO2 Nanotube Arrays: Role of Electrolyte Composition on the Structural, Morphological, Optical, and Photo-electrochemical Properties

The fluoride species present in two different anodizing electrolytes were used to produce TiO2 nanotube arrays (TiO2 NTAs) by simultaneous anodic reaction and chemical dissolution. In this investigation, two different electrolytes were used for the preparation; [Eth-TiO2 NAs: 95 ml ethylene glycol+0.5% NH4F+5 ml DI water] and [Gly-TiO2 NAs: 75 ml glycerine+0.5% NH4F+25 ml DI water]. The effects of the prepared electrolytes used in the synthesis of TiO2 nanotube arrays on structural element composition, morphology, and optical properties are the focus of this study and are characterized by X-ray diffraction (XRD), scanning electron microscopy field emission (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and UV-vis diffusion reflection spectroscopy (DRS), respectively. The photoelectrochemical properties of TiO2 NTAs prepared in different electrolytes were investigated. The photoelectrochemical performance of TiO2 NTAs in Na2SO3 (0.1 M) and Na2S (0.1) was examined under the light of 100 mW/cm2 from a xenon lamp. Comparing the photoelectrochemical (PEC) results of both electrolytes, we find that Eth-TiO2 NTAs contribute a wide surface area resulting in an enhanced PEC response. TiO2 NTs, which were prepared with Eth-TiO2 NTAs, exhibited the highest photocurrent density, 0.326 mA cm–2, and photoconversion efficiency (0.22%).

In Situ Synthesis of Al and V Co-doped TiO2 NTAs Interlayer Enhanced PbO2 Composite for Efficient Zinc Electrowinning

The high overpotential of the oxygen evolution reaction (OER) and the strong corrosion of the anode are the main problems currently facing the zinc hydrometallurgical process. This study achieved the...

Preparation and Photovoltaic Performance of a Composite TiO2 Nanotube Array/Polyaniline UV Photodetector.

TiO2 has great potential for application in UV photodetectors due to its excellent photoelectric response. In this work, composite nanomaterials of TiO2 nanotube arrays (TiO2 NTAs) and polyaniline (PANI) were successfully prepared on titanium sheets using an anodic oxidation electrochemical method. The results showed that the TiO2 NTA/PANI composite materials had excellent UV photosensitivity and responsiveness and good stability and reproducibility. This was mainly attributed to the p-n heterostructure formed inside the TiO2 NTA/PANI composites that hindered the recombination of photogenerated electron-hole pairs and improved their utilization of UV light. This work provides a theoretical basis for the application of metal oxides in UV photodetectors, which is important for the development of UV photodetectors.

Three dimensional titanium dioxide nanotube arrays induced nanoporous structures and stable solid electrolyte interphase layer for excellent sodium storage in ether-based electrolyte

The commercial feasibility of sodium ion batteries (SIBs) is currently limited by the lack of anode materials that simultaneously provide high-rate capability and long cycle stability. In this study, we report three-dimensional (3D) anatase TiO2 nanotube arrays (TiO2 NTAs) as an SIB anode for excellent sodium storage when paired with ether-based electrolyte. The TiO2 NTAs anode exhibits minimal capacity decay over 3000 cycles at 1C and 5000 cycles at 20C in ether-based electrolyte, demonstrating both excellent rate capability and long-term cycle stability. Structural analysis reveals novel discovery that the 3D TiO2 NTAs develop into unique nanoporous structures that sustain during repeated redox cycles in ether-based electrolyte. On the one hand, these nanoporous structures can provide more accessible areas for Na+ intercalation and de-intercalation, enabling fast Na+ intercalation. On the other hand, they also promote the formation of a thin and stable solid electrolyte interphase (SEI) in ether-based electrolyte that facilitates long-term cycle stability. Our investigation advances the performance of TiO2 as a promising SIBs anode material and also offers valuable insights into the impact of unique nanoporous structure to the excellent electrochemical performance.

Zinc Nanoparticles Electrodeposited on TiO2Nanotube Arrays Using Deep Eutectic Solvents for Implantable Electrochemical Sensors

This work reports on the electrodeposition of zinc on nanoporous metal oxide titania nanotube arrays (TiO2 NTAs) using a zinc-containing deep eutectic solvent (Zn2+–DES). The effects of substrate morphology and crystallinity, deposition temperature, zinc concentration, and deposition time on the morphology and electrochemical properties of the Zn/TiO2 NTAs were investigated. Two-dimensional zinc nanohexagons (NHexs) with a mean diameter of ∼300 nm and a thickness of 10–20 nm were decorated onto the TiO2 NTAs (with a pore diameter of ∼80 nm and a tube length of ∼5 μm) via electrodeposition at −1.6 V using Zn2+–DES. Cyclic voltammetry tests on the Zn2+–DES electrolyte revealed an electrochemical window of ∼3.5 V, and the diffusion coefficient of Zn2+ was found to be 4.29 × 10–10 cm2 s–1 at room temperature and 7.10 × 10–10 cm2 s–1 at 40 °C. Zinc nucleation on TiO2 NTA substrates followed an instantaneous model. Using a higher electrodeposition temperature increased the nucleation and growth rate of zinc NHexs, while annealing TiO2 NTAs was found to improve their uniformity and morphology. During the initial stage of deposition, hexagonal close-packed zinc NHexs were found to preferentially grow on tetragonal anatase TiO2 NTAs. The electrodeposition of zinc resulted in lowering the impedance and improving the overall electrochemical properties of TiO2 NTAs. The Zn/TiO2 NTAs developed in this study offer a promising electrocatalyst material system for implantable electrochemical sensors.

Solvothermal preparation of hydrangea-like CuBi2O4 twining TiO2 NTAs with enhanced photoelectrocatalytic dye degradation and hydrogen generation

Ternary oxide semiconductor could effectively adjust the energy band gap and location by changing the elemental ratio, which remarkably benefits the electron transfer and photoelectrocatalytic H2 generation. In this paper, hydrangea-like CuBi2O4 sensitizers were prepared on TiO2 nanotube arrays (TiO2 NTAs) by one-pot solvothermal deposition. The alkali kind showed vital influences on the microstructure and photoelectrocatalytic performance of CuBi2O4/TiO2 NTAs, and the excellent pollutant remediation, photoelectric conversion and photoelectrocatalytic water splitting were achieved by the sample prepared by C6H12N4. Under visible light irradiation, the optimized sample displayed the higher photoelectrocatalytic H2 generation rate (87.42 μmol·cm−2·h−1) than that of samples prepared using other alkali kinds. Moreover, the CuBi2O4/TiO2 NTAs also exhibited high organic dye and Cr(VI) removal performance, and the outstanding photoelectrocatalytic activity indicates the novel strategy for the construction of CuBi2O4/TiO2 NTAs photocatalyst for H2 generation by effective photocatalytic water splitting.

Electrochemical oxidation of carbamazepine in water using enhanced blue TiO2 nanotube arrays anode on porous titanium substrate

In this study, a blue TiO2 nanotube arrays anode on porous titanium substrate (Ti-porous/blue TiO2 NTA) was successfully fabricated by facile anodization and in situ reduction, and was used to investigate the electrochemical oxidation of carbamazepine (CBZ) in aqueous solution. The surface morphology and crystalline phase of the fabricated anode were characterized by SEM, XRD, Raman spectroscopy and XPS, and the electrochemical analysis confirmed that blue TiO2 NTA on Ti-porous substrate had larger electroactive surface area, better electrochemical performance and higher ⋅OH generation ability than that on Ti-plate substrate. The removal efficiency of 20 mg L−1 CBZ in 0.05 M Na2SO4 solution reached 99.75% at 8 mA cm−2 after 60 min electrochemical oxidation, and the rate constant was 0.101 min−1 with low energy consumption. EPR analysis and free radical sacrificing experiments showed that ⋅OH played a key role in the electrochemical oxidation. The possible oxidation pathways of CBZ were proposed through the identification of degradation products, and the main reactions may involve deamidization, oxidization, hydroxylation and ring-opening. Compared with Ti-plate/blue TiO2 NTA anode, Ti-porous/blue TiO2 NTA anode displayed excellent stability and reusability, and is promising to be used in the electrochemical oxidation of CBZ in wastewater.

3D TiO2 nanotube arrays with anatase-rutile phase junction and oxygen vacancies for promoted photoelectrochemical water splitting

Constructing TiO2 phase junction with visible light response, effective separation and transfer of photogenerated charges is desperately needed for photoelectrochemical water splitting. Herein, 3D-TiO2 nanotubes arrays-based phase junction consisted of anatase core and rutile shell as well as oxygen vacancies are successfully fabricated via a new one-step annealing method in Ar atmosphere. The synergistic effect of phase junction and oxygen vacancies not only boosts the separation of photogenerated charges, but also enhances the utilization efficiency of the incident, reflected and/or refracted visible light captured by the 3D configuration. Moreover, the oxygen vacancies can act as electron donors, which could effectively improve the electrical conductivity, and hence further accelerate the separation and transfer of photogenerated charges. Benefiting from these advantages, the optimized 3D-TiO2 NTAs-based phase junction display a maximal photocurrent density of 1.5 mA cm−2 at 0.22 V vs. Ag/AgCl with Faradic efficiency of 100%, which is approximately 1.9 folds higher than that of pure anatase 3D-TiO2 NTAs. The technique and strategy could also be extended to other application of TiO2 NTAs such as solar cells and photocatalysis.

InP/ZnS/ZnS core quantum dots for InP luminescence and photoelectrochemical improvement

Indium phosphide quantum dots (InP QDs) is a promising alternative to traditional Quantum Dots (QDs), improving photoluminescence and other properties. We present the synthesis of ZnS/ZnS double shell QDs by the hot injection method. The diameter of QDs was increased from 3.56 nm for the InP core, 4.7 nm for InP/ZnSQDs (with one-time shelling) and 5.53 nm for InP/ZnS/ZnS (double shelling). This experience revealed that the surface morphology of the QDs has a more regular spherical form and is well dispersed. Moreover, the shell's growth results in a strong improvement of the luminescence. Which is due to the passivation of the surface states by shell comparing with ZnSQDs mono shell coating, with an emission peak of 680 nm. Additionally, to improve the photocurrent efficiency, we report the synthesis of nanostructured films by depositing InPQDs, InP/ZnSQDs, and InP/ZnS/ZnSQDs. Spin coating method was used on the surface of Titanium dioxide nanotubes TiO2 NTAs prepared by the electrochemical anodization process. Photoelectrochemical analyses show significant properties improvement of InP/ZnS/TiO2 and InP/ZnS/ZnS/TiO2 in comparison of InP/TiO2. The measurement shows a photocurrent density around 4×10−6mAcm−2 for the photoanode InP/ZnS/ZnS/TiO2. Which is almost six times higher than that measured on TiO2/InPQDs. This result is attributed to a good compromise between Quantum Dots and TiO2NTAs.

Influence of MnOx deposition on TiO2 nanotube arrays for electrooxidation

TiO2 has demonstrated outstanding performance in electrochemical advanced oxidation processes (EAOPs) due to its structural stability and high oxygen overpotential. However, there is still much room for improving its electrochemical activity. Herein, narrow bandgap manganese oxide (MnOx) was composited with TiO2 nanotube arrays (TiO2 NTAs) that in-situ oxidized on porous Ti sponge, forming the MnOx-TiO2 NTAs anode. XANES and XPS analysis further proved that the composition of MnOx is Mn2O3. Electrochemical characterizations revealed that increasing the composited concentration of MnOx can improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnOx-TiO2 NTAs anode. Meanwhile, the optimal degradation rate of benzoic acid (BA) was achieved using MnOx-TiO2 NTAs with a MnOx concentration of 0.1 mmol L−1, and the role of MnOx was proposed based on DFT calculation. Additionally, the required electrical energy (EE/O) to destroy BA was optimized by varying the composited concentration of MnOx and the degradation voltage. These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.

Low-Temperature Fabrication of TiC Nanotube Arrays by Molten Salt Electrolysis for Supercapacitor Application

A strategy for the synthesis of nanostructured metal carbides that can convert oxides into carbides while maintaining their original nanomorphology is proposed in this study. TiC nanotube arrays (TiC NTAs) were successfully prepared by electrodeoxidation and carbonization in a low-temperature molten salt (600 °C) using TiO2 nanotube arrays (TiO2 NTAs) as precursors. The effects of different factors on the heritability of nanostructures are discussed in detail. TiC NTAs have a highly ordered and directional array structure, a large specific surface area, excellent electrical conductivity, and outstanding chemical stability. Quasi-solid-state supercapacitors based on TiC NTA electrodes exhibit excellent electrochemical energy storage properties such as low charge transfer resistance, high energy density (4.2 μW h cm–2), and excellent cycle stability (90% retention after 10,000 cycles). This study demonstrates a high-performance supercapacitor nanoarray material and provides a general method to synthesize nanostructured metal carbides.

INFLUENCE OF ANATASE TITANIUM DIOXIDE NANOTUBE ARRAYS ON HUMIDITY SENSOR SYNTHESIZED BY ELECTROCHEMICAL ANODIZATION

Humidity sensors have become increasingly important and widely used to improve the quality of life and industrial processes. Over the past decades, titanium dioxide (TiO2) has received wide attention in many promising areas such as sensors, solar cells, and photocatalytic. However, TiO2 required high operating conditions such as high temperatures to examine the crystalline stability phase. This study focuses on highly ordered titanium dioxide nanotube arrays (TiO2 NTAs) film synthesized using the electrochemical anodization method. Annealing temperature effect on the fabricated TiO2 NTAs was investigated. An electrolyte solution was prepared by mixing ammonium fluoride (0.3 wt%) and ethylene glycol (25 ml) with deionized water (2 vol%). Titanium (Ti) sheet was anodized at 35 V for 120 minutes. The films were annealed from 350 °C to 550 °C. FESEM images showed the diameter size of TiO2 NTAs film decreases as the annealing temperatures increases. Results had also shown that the average diameter annealed at 450 °C was around ~50.82 nm while the XRD pattern demonstrated TiO2 NTAs exhibiting an anatase phase with a prominent (101) peak recorded for the sample prepared at 450 °C with a high crystallite size of 29.17 nm. The calculated optical band gap annealed at 450 °C (3.24 eV) is comparable with other literature. The current-voltage characteristic of TiO2 NTAs film reported a high current for 450 °C (1.12 x 10-5 A) with a conductivity of 0.048 S.cm-1 and high sensitivity (287.72).

Photoelectrocatalytic activity of highly ordered TiO2 nanotube arrays modified with polyaniline for tetrabromobisphenol A degradation in water.

Polyaniline (PANI) is a useful conductive polymer material, and has good adsorption property, which makes it a good modification material. In this work, for the sake of highly enhancing the utilization of visible region in sunlight and accelerating photocatalytic degradation of tetrabromobisphenol A (TBBPA), a typical polybrominated flame retardant, titanium dioxide nanotube arrays (TiO2 NTAs) were modified with PANI by chemical and electrochemical polymerization. The coated amount of PANI was controlled via adjusting the polymerization time and the amount of aniline in the electrochemical method. The results demonstrate that the EC-PANI/TiO2 NTAs (synthesized electrochemically) exhibit higher catalytic activity than bare TiO2 NTAs and C-PANI/TiO2 NTAs (synthesized chemically) in photoelectrocatalytic degradation of TBBPA under visible light, and the degradation efficiency for TBBPA could reach 94.37% within 120min. The improved performance was contributed to the synergetic effect of PANI modification which integrated the broad absorption of PANI in visible light region and high catalytic property of TiO2 NTAs. Interestingly, it was also found that the degradation efficiency of TBBPA by EC-PANI/TiO2 was further enhanced by up to 95.74% when the ethanol was present in the reaction system as the hole scavenger. Furthermore, the EC-PANI/TiO2 exhibited excellent stability after 10 cycling experiments. All the results indicated that this new modified material presented strong potential as a photoelectrocatalyst and had great practical applications in the future.

RuO2/IrO2 nanoparticles decorated TiO2 nanotube arrays for improved activity towards chlorine evolution reaction

Dimensionally stable anodes (DSA) have been extensively employed for industrial chlorine evolution reactions (CER). Many efforts have been made to develop nanostructured DSA electrodes to enhance the stability and catalytic activity of CER. Herein, a composite catalyst composed of RuO2/IrO2 decorated TiO2 nanotube arrays (TiO2 NTAs) was proposed for CER applications. 1D TiO2 NTAs were fabricated by electrochemical anodization. RuO2/IrO2 nanoparticles were embedded in TiO2 NTAs by electrochemical deposition. Catalytic activity of RuO2/IrO2-TiO2 NTAs is superior to most CER materials. At a current density of 50 mA cm−2, the overpotential is 1.115 V (vs. SCE) with a Tafel slope of 33.5 mV dec−1 in 5 M NaCl. The RuO2/IrO2-TiO2 NTAs exhibit good selectivity towards oxygen evolution reaction, with a potential separation of 205 mV at 50 mA cm−2. The RuO2/IrO2-TiO2 NTAs also display excellent stability for CER. Almost no attenuation is observed after 50 h test.

Nanostructured Titanium Implant Surface Facilitating Osseointegration from Protein Adsorption to Osteogenesis: The Example of TiO2 NTAs.

Titanium implants have been widely applied in dentistry and orthopedics due to their biocompatibility and resistance to mechanical fatigue. TiO2 nanotube arrays (TiO2 NTAs) on titanium implant surfaces have exhibited excellent biocompatibility, bioactivity, and adjustability, which can significantly promote osseointegration and participate in its entire path. In this review, to give a comprehensive understanding of the osseointegration process, four stages have been divided according to pivotal biological processes, including protein adsorption, inflammatory cell adhesion/inflammatory response, additional relevant cell adhesion and angiogenesis/osteogenesis. The impact of TiO2 NTAs on osseointegration is clarified in detail from the four stages. The nanotubular layer can manipulate the quantity, the species and the conformation of adsorbed protein. For inflammatory cells adhesion and inflammatory response, TiO2 NTAs improve macrophage adhesion on the surface and induce M2-polarization. TiO2 NTAs also facilitate the repairment-related cells adhesion and filopodia formation for additional relevant cells adhesion. In the angiogenesis and osteogenesis stage, TiO2 NTAs show the ability to induce osteogenic differentiation and the potential for blood vessel formation. In the end, we propose the multi-dimensional regulation of TiO2 NTAs on titanium implants to achieve highly efficient manipulation of osseointegration, which may provide views on the rational design and development of titanium implants.

Enhanced photoelectrochemical performances in photocatalytic pollutant degradation and water splitting by direct Z-scheme Bi2Sn2O7/TiO2 NTAs

The construction of ternary metal oxide to improve photoelectrochemical performances of TiO2 photocatalysts is the hot topic in environmental and resource applications. Herein, Bi2Sn2O7 nanoparticles were deposited on TiO2 nanotube arrays (TiO2 NTAs) by the solvothermal technology only by changing reagent concentration. The solar absorption region of TiO2 NTAs was obviously extended into visible light after Bi2Sn2O7 sensitization, and the photoelectric performance was also significantly improved. The high visible light photocurrent density and photovoltage achieved 30.24 μA/cm2 and -0.19 V, and the interface resistance was reduced that benefited the rapid electron transportation. The photocatalytic performances of methyl orange (MO), rhodamine b (RhB), methylene blue (MB) and Cr (VI) removal were enhanced, and 63.76%, 77.34%, 100% and 100% of these pollutants were photoremoved under solar irradiation. Moreover, the construction of direct Z-scheme Bi2Sn2O7/TiO2 NTAs heterojunction was beneficial to the photoelectron transfer and active radical formation, and the experimental results indicated that •OH and •O2- were the decisive species for the dye degradation. The samples also exhibited outstanding photocatalytic water splitting for H2 evolution, and the high efficiency (306.36 μmol·cm−2·h−1) and stability were confirmed. The excellent photocatalytic performances of the Bi2Sn2O7/TiO2 NTAs photoelectrodes showed extensive potential applications in environmental pollution and green resource exploitation.

TiO2 NTAs decorated with thin CuBi2O4 nanosheets for efficient photocatalytic dye degradation and hydrogen generation

Photocatalytic technology is the recent investigation focus because of the wide applications in sewage disposal and new energy generation. In this paper, the optical and photocatalytic properties of TiO2 NTAs were enhanced by the hydrothermal deposition of CuBi2O4 by regulating the precursor concentration. The results indicated that the precursor concentration played remarkable influences on the morphology and photocatalytic ability. The mild reagent concentration was in favor of super-thin CuBi2O4 nanosheet formation. CuBi2O4/TiO2 NTAs with high reagent concentration exhibited high photocurrent and hydrogen production, and showed outstanding performance in the removal of organic dyes and heavy metal ions. The free radical production and the photocatalytic progress were introduced in detail. The high photocatalytic activity exhibits prospective foreground in industrial waste water treatment and novel energy resource development.

Enhancement effect of silver nanoparticles decorated titania nanotube array acting as active SERS substrate

Silver nanoparticles decorated titania nanotube array (Ag-TiO2 NTA) had been designed as active SERS substrate for a sensitive molecule detection. The Ag nanoparticles are deposited on the gaps and nanotube walls of the tubewall-separated TiO2 NTA to form the independent Ag-TiO2 NTA, alternatively on the nanotube wall surface of the tubewall-connected TiO2 NTA to form the interconnected Ag-TiO2 NTA. The microstructure of TiO2 NTA is more critical to affect the SERS performance rather than the deposition cycles. The analytical enhancement factor was accordingly enhanced from 1.67 × 105 for the interconnected Ag-TiO2 NTA up to 9.44 × 105 for the independent Ag-TiO2 NTA. The microstructure-tailored and Ag deposition level-promoted Ag-TiO2 NTA substrate achieved sensitive detection of 4-mercaptobenzoic acid. The superior SERS performance is caused by synergizing the localized electromagnetic field enhancement of Ag nanoparticles and the charge transfer chemical enhancement of TiO2 NTA along with the light scattering enhancement of vertically aligned nanoarray architecture.

Photoelectrochemical performance of tubewall‐separated titanium dioxide nanotube array photoelectrode

AbstractTitanium dioxide nanotube array (TiO2 NTA) grown on titanium substrate has been fabricated as active photoelectrode for organic compound degradation. TiO2 NTA shows the tubewall‐separated nanotube arrangement and anatase crystal structure. Transient photocurrent of 1.86 mA and open‐circuit photovoltage of 0.26 V are determined to keep stable level under ultraviolet (UV) light irradiation, indicating its high photoelectrochemical activity. The cathodic polarization process causes more feasible electron transfer than the equilibrium process and anodic polarization process, which is consistent with the declining current response at an increasing positive potential. The photocatalytic activity of TiO2 NTA is fully evaluated through UV light‐induced photocatalysis and photoelectrocatalysis degradation of organic dye X‐3B as a reactant pollutant. The pseudo‐first‐order reaction rate constant is enhanced from 0.00346 min−1 for photocatalysis to 0.00521 min−1 for photoelectrocatalysis using Langmuir–Hinshelwood kinetic model of heterogeneous catalysis. The tubewall‐separated nanotube structure could induce photoelectron directional transport and provide extra interspace for reactant organic molecule diffusion at accessible surface area. The positive potential applied on TiO2 NTA could further promote photoelectron–hole pair separation. Two strategies of photoelectron generation and photoelectron–hole separation are accordingly adopted to improve its electro‐assisted photocatalytic activity. Therefore, the tubewall‐separated TiO2 NTA could present the promising photoelectrocatalysis application.