TiO2 Nanotube Film Research Articles

Preparation of PbS/TiO2 nanotube films for enhanced photoelectrochemical response and cathodic protection performance

Anodic oxidation method and sonication-assisted successive ionic layer adsorption and reaction (S-SILAR) process were used to prepare TiO2 nanotube films and PbS/TiO2 nanotube films. The effects of impregnation times on photoelectrochemical (PEC) performance of PbS/TiO2 nanotube films were systematically studied. The PEC properties were evaluated by UV–vis DRS, I-t, EIS and coupling potential. When PbS nanoparticles were impregnated for 15 times, the bandgap of PbS/TiO2 was narrowed to 1.4 eV, and the photocurrent density could reach 4.14 mA﹒cm−2, which increased by 12.8 times compared with TiO2. PbS nanoparticles loading onto TiO2 nanotube films is a simple and effective way to enhanced PEC response and cathodic protection performance.

Research on solar cell preparation technology for cutting-edge technology

Flexible dye-sensitized solar cells are highly valued as a practical technology with low production costs. In this paper, we study flexible dye-sensitized solar cells consisting of nanocrystalline TiO2 thin-film electrodes based on titanium metal and counter electrodes based on conductive coated polymers. In order to improve the photoelectric conversion efficiency, nanocrystalline TiO2 film electrodes and TiO2 nanotube film electrodes based on titanium metal and TiO2 nanotube film electrodes are prepared by DC low-field electrophoretic deposition, electrochemical anodizing and screen printing under DC and pulse voltages combined with high-temperature sintering methods; and platinum-carrying counter electrodes and carbon counter electrodes based on conductive coated polymers are prepared by low-temperature techniques, such as constant-current electrochemical deposition and chemical reduction. The mechanisms and characteristics of different preparation methods and optimization techniques are analyzed and discussed, and the performances of nanocrystalline TiO2 thin film electrodes and counter electrodes prepared by different methods are compared. On this basis, the all-flexible solar cell is developed, and the maximum photoelectric conversion efficiency reaches 6.74%.

Highly ordered TiO2 nanotube films photo-decorated with Ag nanoparticles as SERS platforms: Relationship between morphology and enhancement

In this work, we synthesized TiO2 nanotube films (TiO2-NTFs) photo-decorated with Ag nanoparticles for their application in Surface-Enhanced Raman Scattering. In situ growth of Ag nanoparticles was performed through the exposure of anodic TiO2-NTFs to UVC radiation following their pretreatment in an AgNO3 aqueous solution. High nanoparticle surface densities, with uniform coverage on the film surface, and controllable size, were prepared by regulating the UVC exposure time and AgNO3 concentration. Ag nanoparticles nucleation and growth also take place along the tubes, including at the bottoms. The evidence obtained also indicates that a high enough AgNO3 concentration inhibits the well-known water-assisted crystallization mechanism, typically promoted when TiO2-NTFs are exposed for prolonged times in aqueous media. The performance of the photo-decorated films in Surface-Enhanced Raman Scattering shows that the presence of Ag nanoparticles plays a key role, and both the nanoparticle surface density and size must be regulated to promote a large number of hot-spots.

Simulation and fabrication of titanium dioxide thin films for supercapacitor electrode applications

Nanostructured thin-film electrode materials are proposed for supercapacitors due to their outstanding performance over bulk materials. In this work, we fabricated a TiO2 nanotube film over a titanium foil using a top-down approach for supercapacitor electrodes. We noticed that the fabricated nanotubes are uniform and well aligned, confirmed by FESEM; the TiO2 nanotube parameters were further simulated using COMSOL Multiphysics. Simulations show an areal capacitance of 1.19393 pF/cm2 with oxidation and reduction peak currents of 6.18921×10[Formula: see text] A and −6.0320×10[Formula: see text] A, respectively, at 10 mV/s scan rate. The as-prepared nanotubes show a poor areal capacitance of 1.0193 F/cm2, which is improved to 12.8764 F/cm2 at a scan rate of 10 mV/s, that is approximately 12.63 times with oxidation and reduction peak currents of 0.129 mA/cm2 and −0.105 mA/cm2, respectively, by performing an electrochemical etching. Further, the surface roughness of both as-prepared and etched samples is studied to comment on their surface area changes. The effect of the etched sample is studied, compared and validated with simulation, which reveals that the etched TiO2 nanotubes thin-film sample shows considerable similarity with the simulation results.

Study on the photoelectrocatalytic activity of reduced TiO2 nanotube films for removal of methyl orange

Abstract The reduced TiO2 film on which a photoelectrocatalytic (PEC) process had occurred was created from TiO2 nanotube film electrodes by the electrochemical reduction method. The obtained samples’ structure and morphology were characterized using UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, photoluminescence, and X-ray diffraction. Cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, chronoamperometry, UV-Vis absorbance spectroscopy, and Mott–Schottky plots were employed to examine the electrochemical and photoelectrochemical activities of the prepared electrodes. The results showed that the optimal conditions of cathodic polarization were a potential of −1.4 V for 60 min. The reduced TiO2 nanotube film electrode had better photoelectrochemical activities than pristine TiO2 under UV light due to the higher photocurrent density (13.7 mA‧cm−2) at 1.5 V (vs Ag/AgCl, sat. KCl reference electrode) compared to pristine TiO2 achieving 7.3 mA‧cm−2, indicating more effective charge separation and transport. The degradation of methyl orange (MO) on pristine TiO2 and reduced TiO2 electrodes was carried out in electrocatalytic (EC) and PEC conditions. The PEC process on the reduced TiO2 electrode had the highest MO processing efficiency (98.4%), and the EC process for MO removal on reduced TiO2 had higher efficiency (95.1%) than the PEC process on pristine TiO2 (89.2%).

Enhanced interfacial solar driven water evaporation performance of Ti mesh through growing TiO2 nanotube and applying voltage

Interfacial solar driven water evaporation (ISDWE) technology has been widely studied to desalinate seawater in aiming to alleviate the scarcity of clean water. In this paper, the ISDWE performance of Ti mesh was enhanced by anodized TiO2 nanotube film and applied voltage, and the water evaporation rate increased from 1.20 kg•m−2•h−1 to 2.48 kg•m−2•h−1. Due to hydrophilic and nanoporous nature of TiO2 nanotube film, the solar absorptivity, wettability of Ti mesh was improved, the water evaporation enthalpy was reduced, and the water evaporation rate reached 1.98 kg•m−2•h−1. For the superior ISDWE performance with applied voltage, electrothermal effect and internal electrical filed were proved to be contributing factors. The solar irradiation can enhance the electrothermal effect for the semiconducting nature of TiO2. The internal electrical field can optimize the solar absorptivity and water evaporation enthalpy through doping TiO2 and breaking water clusters. Moreover, the applied voltage also increased the salt-resistance property of Ti mesh coated with TiO2 nanotube film. When increasing NaCl concentration, stable water evaporation rate was attainable under 1.2 V, whereas continuous deceleration of water evaporation occurred without external voltage. Therefore, our study provides strategies for achieving high efficient and salt-free seawater desalination by ISDWE technology.

High-efficiency photocathodic protection performance of novel MnIn2S4/TiO2 n-n heterojunction films for Q235 carbon steel in chloride-containing simulated concrete pore solution

In this work, the n-type TiO2 nanotube film was modified successfully by n-type MnIn2S4 nanoparticles with one-step hydrothermal method, and a novel MnIn2S4/TiO2 heterojunction material with excellent photoelectrochemical properties was constructed firstly. Owing to the modification, the light response range of MnIn2S4/TiO2 nanocomposites was extended to the visible light region. Benefiting from the presence of type II n-n heterojunction with built-in electric field effects in the nanocomposites, the photogenerated carriers recombination rate decreased significantly. In addition, the photocathodic protection effects of MnIn2S4/TiO2 (MIS/T) photoanodes on Q235 carbon steel (Q235 CS) immersed in simulated concrete pore solution containing chloride were investigated. Under visible light irradiation, the cathodic protection current density of MIS/T-2 photoanode was found to be more than 30 μA/cm2 and over 10 times that of T photoanode. The MIS/T-2 photoanode has good long-term photochemical stability and maintains excellent photocathodic protection effect on Q235 CS (OCP value are about - 870 mV (vs. SCE)) under visible light irradiation. The amount of MnIn2S4 nanoparticles deposited on the TiO2 film could affect the photoelectrochemical properties of MnIn2S4/TiO2 n-n heterojunctions and an appropriate number of the nanoparticles, corresponding to the best cathodic protection performance was revealed.

Highly Efficient CuInSe2 Sensitized TiO2 Nanotube Films for Photocathodic Protection of 316 Stainless Steel

CuInSe2 nanoparticles were successfully deposited on the surface of TiO2 nanotube arrays (NTAs) by a solvothermal method for the photocathodic protection (PCP) of metals. Compared with TiO2 NTAs, the CuInSe2/TiO2 composites exhibited stronger visible light absorption and higher photoelectric conversion efficiency. After 316 Stainless Steel (SS) was coupled with CuInSe2/TiO2, the potential of 316 SS could drop to −0.90 V. The photocurrent density of CuInSe2/TiO2 connected to 316 SS reached 140 μA cm−2, which was four times that of TiO2 NTAs. The composites exhibited a protective effect in the dark state for more than 8 h after 4 h of visible light illumination. The above could be attributed to increased visible light absorption, the extended lifetime of photogenerated electrons, and generation of oxygen vacancies.

Nanostructured Superhydrophobic Titanium-Based Materials: A Novel Preparation Pathway to Attain Superhydrophobicity on TC4 Alloy.

This study develops the nanostructured superhydrophobic titanium-based materials using a combined preparation method of laser marking step and the subsequent anodizing step. The structural properties were determined using an X-ray diffractometer (XRD) and scanning electron microscope (SEM), while the performance was explored by wear and corrosion tests. The laser marking caused a rough surface with paralleled grooves and protrusions, revealing surface superhydrophobicity after organic modification. The anodizing process further created a titanium oxide (TiO2) nanotube film. Both phase constituent characterization and surface elemental analysis prove the uniform nanofilm. The inert nanosized oxide film offers improved stability and superhydrophobicity. Compared to those samples only with the laser marking process, the TiO2 nanotube film enhances the corrosion resistance and mechanical stability of surface superhydrophobicity. The proposed preparation pathway serves as a novel surface engineering technique to attain a nanostructured superhydrophobic surface with other desirable performance on titanium alloys, contributing to their scale-up applications in diverse fields.

A novel electric-assisted photocatalytic technique using self-doped TiO2 nanotube films

Semiconductor doping is an effective strategy for improving the light absorption efficiency and the photogenerated carrier transport in photocatalysts. However, bulk defects induced by doping act as recombination centers, accelerating the recombination of carriers, which is detrimental to the photocatalytic performance. In this study, a novel electric-assisted photocatalytic technique was developed to reduce the recombination of the carriers trapped by the defects. The technique involves applying a low external voltage to a self-doped TiO2 nanotube film, without any electrolyte and counter electrode. The remarkable improvement in the charge carrier dynamics under the electric assistance is attributed to the significant promotion of photogenerated electron fluxes and prevention of charge recombination. The electric-assisted photocatalytic technique is compatible with a liquid- or a gas-phase reactive system, e.g., water splitting, H2O2 synthesis, and CO2 photoreduction. The technique is sufficiently advanced to allow scale-up of the photocatalytic process from laboratory scale to industrial-scale.

Fabrication of CdSe/ZnIn2S4 modified TiO2 nanotube composite and its application in photoelectrochemical cathodic protection

In order to obtain a TiO2 nanocomposite film with enhanced photoelectrochemical properties for corrosion protection of metals, a TiO2 nanotube film was fabricated on a Ti substrate via anodization, then ZnIn2S4 nanosheets and CdSe nanoparticles were sequentially deposited on the TiO2 film by hydrothermal treatment and electrodeposition, respectively. The CdSe/ZnIn2S4 co-modified TiO2 heterostructured nanocomposite film showed remarkably enhanced visible light absorption and photoelectrochemical properties. Under white light irradiation, the photocurrent density of the nanocomposite film in the mixed solution with 0.1 M Na2S and 0.1 M Na2SO3 was 33 times higher than that of the TiO2 film. The nanocomposite could negatively shift the potential of the coupled 403 stainless steel immersed in a 0.5 M NaCl solution by 440 mV, showing efficient photoelectrochemical cathodic protection.

Controlling anodization time to monitor film thickness, phase composition and crystal orientation during anodic growth of TiO2 nanotubes

Anodic TiO2 nanotube (TNT) films show promises for photon-driven catalytic, electricity storage and chemical processes. The film thickness of anodic TNT is known to affect its performance in optical and electronic applications. Also, factors affecting the morphology and dimensions of anodic TNT films are rather well-known. However, the knowledge on phase transition and composition in the growth of anodic TiO2 from the titanium metal is very limited. In this work, the anodization time is controlled in intervals of 10, 60, 300, 1000, 2000 and 5000 s to investigate its effect on phase composition and transition, and the morphology of the anodic TNT during the growth process. Even though the mechanism of anodic TNT formation is still under debate, the scanning electron microscope results support bottom-up tube growth with evidence of a compact layer. It was also found that the Richards growth model is applicable to correlate growth time and film thickness. Finally, the phase transition, crystal orientation and pore formation during the anodic process are further discussed.

TiO2 Nanotube Hydroxyapatite Nanocomposite as Methanol Sensor

AbstractIn the present work, it has successfully demonstrated the utilization of TiO2 nanotube (TNT) and hydroxyapatite (HAp) nanocomposite films by screen printing techniques material for sensing methanol at lower temperature and lower concentrations. Preparation of modified material using HAp blended with TNT by mechanical mixing in different height percentages. The 2 wt% TNT‐HAp nanocomposite film exhibits pronounced sensing behavior for the detection of alcohol vapor even at 10 ppm. The operating temperature is observed to be 30°C for methanol, whereas for the same nanocomposite material fast response and recovery time are 100 and 30 s, respectively, as compared with pure HAp, TNT. These results concluded that nanocomposite of TNT and HAp is capable to sense alcohol vapors with their existence in ambient as low as 10 ppm concentration.

WO3 as Additive for Efficient Photocatalyst Binary System TiO2/WO3

Abstract Two different methods of synthesis of TiO2/WO3 heterostructures were carried out with the aim to increase photocatalytic activity. In this study, anodic TiO2 nanotube films were synthesized by electrochemical anodization of titanium foil. WO3 particles were applied to anodic Ti/TiO2 samples in two different ways – by electrophoretic deposition (EPD) and insertion during the anodization process. Structural and photocatalytic properties were compared between pristine TiO2 and TiO2 with incorporated WO3 particles. Raman mapping was used to character-ise the uniformity of EPD WO3 coating and to determine the structural composition. The study showed that deposition of WO3 onto TiO2 nanotube layer lowered the band gap of the binary system compared to pristine TiO2 and WO3 influence on photo-electrochemical properties of titania. The addition of WO3 increased charge carrier dynamics but did not increase the measured photo-current response. As the WO3 undergoes a phase transition from monoclinic to orthorhombic at approximately 320 ℃ proper sequence WO3 deposition could be beneficial. It was observed that secondary heat treatment of WO3 lowers the photocurrent.

Drastic promotion of the photocathodic protection property of TiO2 nanotube films decorated with n-type CuInS2 nanoparticles

The n-type CuInS2 nanoparticles were deposited successfully on n-type TiO2 nanotube surface via the successive ion layer absorption and reaction (SILAR) technique. Compared with the pure TiO2, the photoresponse of CuInS2/TiO2 films is expanded to the visible region, indicating an excellent visible light utilization rate and improved photoelectric conversion efficiency. Benefiting from the favorable n-n heterojunction structure, the photocurrent density of CuInS2/TiO2 photoanode under visible light irradiation exceeded 40 μA/cm2, which was 8 times that of the TiO2. The potential of the coupled 316L stainless steel in 3.5 wt% NaCl aqueous solution was droped by − 850 mV in the presence of CuInS2/TiO2 films, which showed a remarkable photocathode protection performance of n-n type CuInS2/TiO2 heterojunction materials.

Novel TiO2 nanotubes films with silk fibroin substrate

The poor adhesion of anodic TiO2 nanotubes (TiO2 NTbs) on titanium substrates obviously affects applications in many fields. Herein, novel films of silk fibroin (SF) substrate based TiO2 nanotubes were successfully prepared. The work of this thesis include the followings: 1. The composite films with only hundreds of nanometers tube length can be obtained. 2. The film is fiexible and has enough mechanical strength after peel off from Ti substrate, which is beneficial to further application. 3. The nanotube structure remains unchanged. 4. The barrier layer of TiO2 nanotubes can be removed by HF etching and the opened TiO2 nanotube arrays lied on SF substrate were successfully prepared.

Ag/SnO2/TiO2 nanotube composite film used in photocathodic protection for stainless steel

A TiO2 nanotube film was fabricated on a Ti foil via anodization, SnO2 quantum dots were deposited on the film by hydrothermal treatment, and then Ag nanoparticles were formed on the SnO2/TiO2 film by pulse electrodeposition to obtain a Ag/SnO2 co-modified TiO2 composite photoanode with good photocathodic protection performance and charge storage ability. The properties of the composite film were investigated by surface analyses, UV–vis and fluorescence spectroscopies, and photoelectrochemical measurements. The results showed that the light absorption of the Ag/SnO2/TiO2 film was extended into the visible region compared with the TiO2 film. The photocurrent intensity of the composite film was two times as high as that of the TiO2 film. The composite photoanode under illumination by white light made the potential of the coupled 403 stainless steel (403SS) in a 0.5 M NaCl solution drop by 475 mV in contrast with its corrosion potential, showing an enhanced photocathodic protection effect. It is noteworthy that the 403SS potential was still 270 mV lower than the corrosion potential within 22.5 h after cutting off the illumination, demonstrating that the cathodic protection could be maintained through the charge storage ability of the composite photoanode.

A TiO2 nanotubes film with excellent antireflective and near-perfect self-cleaning performances

SiO2/TiO2 composite films have been frequently used to realize the functions of self-cleaning and antireflection. Increasing the TiO2 volume ratio in SiO2/TiO2 composite film is beneficial to enhance the self-cleaning effect, while high TiO2 content leads to a strong Rayleigh scattering and depresses the antireflective performance, resulting in a bottleneck problem for the dual-functional application. Here, we have achieved a high-quality TiO2 nanotubes film with excellent antireflective and near-perfect self-cleaning performances. Ultrasound assisted pickling method has been developed to effectively prepare the well-dispersed protonated titanate nanotubes colloid. After spin-coating and annealing treatment, glass substrate coated with double-side TiO2 nanotubes film has a peak transmittance of 99.2 % and average transmittance of 97.4 % at 400−800 nm. Ultra-high porosity of TiO2 nanotubes film (80 %) and ultra-fine size of TiO2 nanotubes (8.6 nm in outer diameter) lead to excellent antireflective performance. With high UV absorptivity (80 % at 254 nm) and formal quantum efficiency of stearic acid (10.9 × 10−3), TiO2 nanotubes film shows near-perfect self-cleaning performance. A persistent anti-fogging ability is also presented. This study demonstrates the feasibility to fabricate pure TiO2 antireflective coating for glass substrate, extends application field of the classic TiO2 nanotubes, and sheds lights on the practical applications of high-powered TiO2 nanotube-based multi-functional films.

Hydrothermal synthesis of rutile TiO2 nanotubes film on Ti foil for photocatalytic degradation

One-dimensional TiO2 nanotubes film was synthesized on the Ti foil oxidized at 800℃ by hydrothermal method in a highly alkaline solution. The crystal structure, morphology and chemical state of the samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. The result indicates that the TiO2 nanotubes film still remains rutile phase structure after hydrothermal treatment. The growth mechanism of TiO2 nanotubes is also discussed that includes dissolution, nucleation and growing process. The photocatalytic activity of TiO2 film is remarkably improved after hydrothermal reaction. Due to the one-dimensional tubular structure, TiO2 nanotubes film hydrothermally synthesized for 6 hours displays the highest photocatalytic degradation rate of methylene blue

Surface treatment of titanium by in-situ anodizination and NiO photodeposition: enhancement of photoelectrochemical properties for water splitting and photocathodic protection of stainless steel

Chromium-doped TiO2 nanotubes (CT) film on titanium substrates was prepared by an in-situ electrochemical anodizing method and then a wide range time was used for photodeposition of NiO on the surface of CT to optimize the condition for the fabrication of NiO-chromium-doped TiO2 nanotubes (NCT). Various techniques were used to characterization which confirms the anatase form of TiO2 as well as the presence of NiO. The UV–Vis spectra exhibit that deposited of NiO on the surface of CT progressively enhances visible light absorption. Photoelectrochemical performance of as-prepared samples was studied in the presence and absence of light which showed that NCT samples are markedly beneficial for reducing photo generated charges recombination. NCT2 sample effectively increased photocurrent density four times more than the bare CT sample and showed the maximum amount of H2 evolution during water splitting after 60 min. In addition, Tafel tests are performed to investigate the photocathodic protection of as-prepared samples for 403 stainless steel. It was observed that the photocathodic protection performance is achieved for NCT2 which prepared at a photodeposition time of 20 min.