Simple Method to Fabricate Au Nanoparticle-Decorated TiO2 Nanotube Arrays for Enhanced Visible Light Photocurrent

Au nanoparticle-decorated TiO2 nanotube arrays are prepared by a simple method, which is a thermal annealing thin gold film deposited on anodie oxidized TiO2 nanotube arrays. These electron microscope images present that Au nanoparticles are well dispersed within the wall and on the surface of the XiO2 nanotubes. Meanwhile, the morphologies of Au nanoparticles can be controlled by changing the thickness of the deposited gold film. Associ- ated with the excitation of localized surface plasmon resonances, the prepared Au nanoparticle-decorated TiO2 nanotube arrays could work as visible light responsive photocatalysts to produce a greatly enhanced photocurrent density. By varying the initial gold film thickness, such Au nanoparticle-decorated TiO2 nanotube arrays could be optimized to obtain the highest photocurrent generation efficiency in the visible and UV light regions.

Nitrogen-doped carbon encapsulated in mesoporous TiO2 nanotubes for fast capacitive sodium storage

Controllable synthesis of insertion-type anode materials with beneficial micro-and nanostructures is a promising approach for the synthesis of sodium-ion storage devices with high-reactivity and excellent electrochemical performance.In this study,we developed a sacrificial-templating route to synthesize TiO_(2)@N-doped carbon nanotubes(TiO_(2)@NC-NTs)with excellent electrochemical performance.The asprepared mesoporous TiO_(2)@NC-NTs with tiny nanocrystals of anatase TiO_(2) wrapped in N-doped carbon layers showed a well-defined tube structure with a large specific surface area of 198 m^(2) g^(-1) and a large pore size of~5 nm.The TiO_(2)@NC-NTs delivered high reversible capacities of 158 m A h g^(-1) at 2 C(1 C=335 m A g^(-1))for 2200 cycles and 146 m A h g^(-1) at 5 C for 4000 cycles,as well as an ultrahigh rate capability of up to 40 C with a capacity of 98 m A h g^(-1).Even at a high current density of 10 C,a capacity of 138 m A h g^(-1) could be delivered over 10,000 cycles.Thus,the synthesis of mesoporous TiO_(2)@NC-NTs was demonstrated to be an efficient approach for developing electrode materials with high sodium storage and long cycle life.

Fast Growth of Highly Ordered TiO2 Nanotube Arrays on Si Substrate under High-Field Anodization

Highly ordered TiO_2 nanotube arrays(NTAs) on Si substrate possess broad applications due to its high surfaceto-volume ratio and novel functionalities, however, there are still some challenges on facile synthesis. Here, we report a simple and cost-effective high-field(90–180V) anodization method to grow highly ordered TiO_2 NTAs on Si substrate,and investigate the effect of anodization time, voltage, and fluoride content on the formation of TiO_2 NTAs. The current density–time curves, recorded during anodization processes, can be used to determine the optimum anodization time. It is found that the growth rate of TiO_2 NTAs is improved significantly under high field, which is nearly 8 times faster than that under low fields(40–60 V). The length and growth rate of the nanotubes are further increased with the increase of fluoride content in the electrolyte.

Photocatalytic Oxidation of Low Molecular Weight Hydrocarbon Gases over Pt-TiO2 Nanotubes

Pt-TiO2 nanotubes with tube diameter of -120 nm and uniformly dispersed Pt particles（size of -2 nm） were successfully synthesized via a carbon nanotube（CNT） templating method followed by a photo-deposition processing of Pt nanoparticles. The as-obtained Pt-TiO2 NTs possess both enhanced visible light absorption and reduced recombination of photogenerated electrons and holes. These merits boost the Pt-TiO2 NTs an excellent photocatalytic material toward photooxidation of a variety of low molecular hydrocarbons under atmospheric environment.

Analysis of the factors controlling performances of Au-modified TiO2 nanotube array based photoanode in photo-electrocatalytic(PECa)cells

The efficiency of photo-electrocatalytic（PECa） devices for the production of solar fuels depends on several limiting factors such as light harvesting, charge recombination and mass transport diffusion. We analyse here how they influence the performances in PECa cells having a photo-anode based on Au-modified TiOnanotube（TNT） arrays, with the aim of developing design criteria to optimize the photo-anode and the PECa cell configuration for water photo-electrolysis（splitting） and ethanol photo-reforming processes.The TNT samples were prepared by controlled anodic oxidation of Ti foils and then decorated with gold nanoparticles using different techniques to enhance the visible light response through heterojunction and plasmonic effects. The activity tests were made in a gas-phase reactor, as well as in a PECa cell without applied bias. Results were analysed in terms of photo-generated current, Hproduction rate and photoconversion efficiency. Particularly, a solar-to-hydrogen efficiency of 0.83% and a Faradaic efficiency of 91%were obtained without adding sacrificial reagents.

Synthesis and photoelectrical performance of nanoscale PbS and Bi2S3 co-sensitized on TiO2 nanotube arrays

TiO2 films have been widely applied in photo- voltaic conversion techniques. TiO2 nanotube arrays （TiO2 NAs） can be grown directly on the surface of metal Ti by the anodic oxidation method. Bi2S3 and PbS nanoparticles （NPs） were firstly co-sensitized on TiOa NAs （denoted as PbS/Bi2S3（n）/TiO2 NAs） by a two-step process containing hydrothermal and sonication-assisted SILAR method. When the concentration of Bi3＋ is 5 mmol/L, the best photoelectrical performance was obtained under simulated solar irradiation. The short-circuit photocurrent （Jsc） and photoconversion efficiency （η） of PbS/Bi2S3（5）/TiO2 NAs electrode were 4.70 mA/cm and 1.13 %, respectively.

Preparation and Characterization of TiO2 Nanotubes Decorated by CuO and CeO2 Particles

A novel catalyst,TiO2 nanotubes(TiO2 NTs)composite decorated by CuO and CeO2 particles,was prepared by a simple and cost-effective method.The TiO2 NTs were fabricated by the hydrothermal method,and CuO and CeO2 particles loaded onto TiO2 NTs(CuO/CeO2@TiO2 NTs)were prepared by the water bath heating method.The CuO/CeO2@TiO2 NTs were investigated and characterized by transmission electron microscope(TEM),energy dispersive spectrometer(EDS),photoluminescence(PL),X-ray diffractometer(XRD)and ultraviolet-visible light diffuse reflectance spectrum(UV-Vis DRS).Both the p-n heterojunction formed at the p-CuO and n-TiO2 interfaces and the highly induced electron transfer of CeO2 can greatly promote the separation of electrons-holes.Therefore,CuO/CeO2@TiO2 NTs show enhanced absorption and have potential applications in photocatalysis.

Effect of size and crystalline phase of TiO2 nanotubes on cell behaviors: A high throughput study using gradient TiO2 nanotubes

The research of TiO2 nanotubes(TNTs)in the field of biomedicine has been increasingly active.However,given the diversity of the nanoscale dimension and controversial reports,our understanding of the structure-property relationships of TNTs is not yet complete.In this paper,gradient TNTs with a wide diameter range of 20-350 nm were achieved by bipolar electrochemistry and utilized for a thorough high-throughput study of the effect of nanotube dimension and crystalline phase on protein adsorption and cell behaviors.Results indicated that protein adsorption escalated with nanotube dimension whereas cell proliferation and differentiation are preferred on small diameter(<70 nm)nanotubes.Large diameter anatase nanotubes had higher adsorption of serum proteins than as-prepared ones.But only as-prepared small diameter nanotubes presented slightly higher cell proliferation than corresponding annealed nanotubes whereas there was no discernible difference between as-prepared and annealed nanotubes on cell differentiation for the entire gradient.Those findings replenish previous research about how cell responses to TNTs with a wide diameter range and provide scientific guidance for the optimal design of biomedical materials.

Fabrication, modification and environmental applications of TiO2 nanotube arrays （TNTAs） and nanoparticles

Among the semiconductors, titanium dioxide has been identified as an effective photocatalyst due to its abundance, low cost, stability, and superior electronic energy band structure. Highly ordered nanotube arrays of titania were produced by anodization and mild sonication. The band gap energy of the titania nanotube arrays was reduced to 2.6 eV by co-doping with Fe, C, N atoms using an electrolyte solution containing K3Fe（CN）6. The photo- conversion of phenol in a batch photoreactor increased to more than 18% based on the initial concentration of phenol by using a composite nanomaterial consisting of titania nanotube arrays and Pt/ZIF-8 nanoparticles. A layer-by- layer assembly technique for the deposition of titania nanoparticles was developed to fabricate air filters for the degradation of trace amounts of toluene in the air and preparation of superhyrophobic surfaces for oil-water separation and anti-corrosion surfaces.

Improving the fretting biocorrosion of Ti6Al4V alloy bone screw by decorating structure optimised TiO2 nanotubes layer

TiO2 nanotubes(NT)has been demonstrated its potential in orthopaedic applications due to its enhanced surface wettability and bio-osteointegration.However,the fretting biocorrosion is the main concern that limited its successfully application in orthopaedic application.In this study,a structure optimised thin TiO2 nanotube(SONT)layer was successfully created on Ti6Al4V bone screw,and its fretting corrosion performance was investigated and compared to the pristine Ti6Al4V bone screws and NT decorated screw in a bone-screw fretting simulation rig.The results have shown that the debonding TiO2 nanotube from the bone screw reduced significantly,as a result of structure optimisation.The SONT layer also exhibited enhanced bio-corrosion resistance compared pristine bone screw and conventionally NT modified bone screw.It is postulated that interfacial layer between TiO2 nanotube and Ti6Al4V substrate,generated during structure optimisation process,enhanced bonding of TiO2 nanotube layer to the Ti6Al4V bone screws that leading to the improvement in fretting corrosion resistance.The results highlighted the potential SONT in orthopaedic application as bone fracture fixation devices.

Enhanced Efficiency of Dye-sensitized Solar Cells Using rGO@TiO2 Nanotube Hybrids

We established a novel strategy for the synthesis of reduced graphene oxide（rGO）@TiO2 nanotube hybrids using an 18 W UV-assisted photo-catalytic reduction method for utilization as photo-anode of dye-sensitized solar cells（DSSCs）. The photo-conversion efficiency of DSSCs was significantly enhanced after the addition of rGO, and in addition, the photo-anode showed decreased internal resistance. Analysis of rGO@TiO2 hybrids by transmissions scanning electron microscopy（TEM）, X-ray diffraction（XRD）, Raman spectra, N2 adsorption and desorption, atomic force microscopy（AFM） and X-ray photoelectron speetroscopy（XPS） demonstrates that the rGO modified TiO2 nanotubes can increase the short-circuit current and the conversion efficiency of dye-sensitized solar cells. The efficiency is improved by almost two folds as much compared to those of the bare TiO2 nanotubes.

Growth of TiO2 Nanotube on Titanium Substrate to Enhance its Biotribological Performance and Biocorrosion Resistance

TiO2 nanotubes(NTs)have a great potential in improving the osetointegration of titanium(Ti)-based biomaterials.Much efforts have been made to evaluate the biological performance of the TiO2 nanotube in regulating protein adsorption and cells attachments.As often used in orthopaedic applications,although biotribological performance and biocorrosion are important issues in these applications,few researches have been reported on the biotribological perfonnance of NT layers.This paper reports the preparation of a structure-optimised TiO2 NT(SO-NT)material via a multi-step oxidation strategy,as well as its biotribological and biocorrosion behaviours.In this procedure,an interfacial bonding layer of approximately 120 nm=150 nm was first formed on the titanium substrate,which was then joined to the NT bottoms.The mechanical testing with respect to impact,bending,and biotribological perfbnnance have demonstrated the resultant SO-NT layer possess improved mechanical stability compared to conventional NT.The uniform hyperfine interfacial bonding layer with nano-sized grains exhibited a strong bonding to NT layer and Ti substrate.It was observed that the layer not only effectively dissipates external impacts and shear stress but also acts as a good corrosion resistance barrier to prevent the Ti substrate from corrosion.Theoretical models were proposed to analyze and predict the shear performance and corrosion-resistance mechanisms of the resultant material.The obtained results demonstrated that the SO-NT material has great potential in orthopaedic applications.

Electro-Optics and Band Gap Energies of Nanosilver-Coated TiO2 Nanotubes on Titanium Metal

TiO2 nanotubes on Ti metal surface were prepared by the electrochemical anodization method. Then, nanosilver was deposited onto the nanotubes by the electroless dip coating and the anodization. The obtained TiO2 nanotubes were examined by using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, cyclic voltammetry, and UV–Vis. The electrochemical band gap（Eg^CV） of the nanosilver-coated TiO2 nanotubes prepared by the anodization was found as 1.54 eV. Using the UV–Vis measurements, the optical band gap energy（Eg^op.） was calculated as 1.51 eV for the Ag/TiO2 nanotubes obtained by electroless dip coating. The electrical conductivity of the TiO2 nanotubes also increased from 3.0 × 10^-4 to 34.7 S/cm after nano Ag deposition by the anodization method.These Ag/TiO2 nanotubes with low band gap and high electrical conductivity are desirable for the applications in electronics, Li-ion batteries, and solar cells.

Direct Electrochemistry of Hemoglobin on Vertically Aligned Carbon Hybrid TiO2 Nanotubes and Its Highly Sensitive Biosensor Performance

The present work is focused on developing a novel biomaterial platform to achieve enhanced direct electron transfer （DET） of hemoprotein and higher biosensor performance on vertically aligned carbon hybrid TiO2 nanotubes （C-TiO2 NTs）. Using a simple surfactant-assisted method, controllable hybridization of TiO2 NTs with conductive amorphous carbon species is realized. The obtained C-TiO2 NTs is ingeniously chosen to serve as an ideal ＂vessel＂ for protein immobilization and biosensor applications. Results show that the appropriate hybridization of C into TiO2 NTs leads to a much better conductivity of TiO2 NTs without destroying their preponderant tubular structures or damaging their excellent biocompatibility and hydrophilicity. When used in loading proteins, the C-TiO2 NTs can be used as a super vessel for rapid and substantive immobilization of hemoglobin （Hb）, with a large surface electroactive Hb coverage （I＊） of 3.3 × 10 9 mol·cm^-2. Enhanced DET of Hb is commendably observed on the constructed Hb/C-TiO2 NTs biosensor with a couple of well-defined redox peaks in a fast electron transfer process. The biosensor further exhibits fast response, high sensitivity and stability for the amperometric biosensing of H202 with the detection limit as low as 3.1 × 10^-8 mol/L.

Fabrication, Characterization and Optical Properties of TiO2 Nanotube Arrays on Boron-doped Diamond Film Through Liquid Phase Deposition

TiO2 nanotube（TiNT） arrays were deposited on boron-doped diamond films by a liquid-phase deposition method with ZnO nanorod arrays as the template.The different morphologies of TiNTs have been obtained by controlling the morphology of ZnO template.The X-ray diffraction and energy-dispersive X-ray analysis show that the ZnO nanorod array template has been removed in the TiNTs formation process.The crystalline quality of the TiNTs is improved by increasing the annealing temperature.The band gap of the TiNTs is about 3.25 eV estimated by the UV-Vis absorption spectroscopy,which is close to the value of bulk TiO2.In the photoluminescence spectrum,a broad visible emission in a range of ca.550-750 nm appears due to the surface oxygen vacancies and defects.

Deciphering controversial results of cell proliferation on TiO2 nanotubes using machine learning

With the rapid development of biomedical sciences,contradictory results on the relationships between biological responses and material properties emerge continuously,adding to the challenge of interpreting the incomprehensible interfacial process.In the present paper,we use cell proliferation on titanium dioxide nanotubes(TNTs)as a case study and apply machine learning methodologies to decipher contradictory results in the literature.The gradient boosting decision tree model demonstrates that cell density has a higher impact on cell proliferation than other obtainable experimental features in most publications.Together with the variation of other essential features,the controversy of cell proliferation trends on various TNTs is understandable.By traversing all combinational experimental features and the corresponding forecast using an exhausted grid search strategy,we find that adjusting cell density and sterilization methods can simultaneously induce opposite cell proliferation trends on various TNTs diameter,which is further validated by experiments.This case study reveals that machine learning is a burgeoning tool in deciphering controversial results in biomedical researches,opening up an avenue to explore the structure-property relationships of biomaterials.

BiVO4/TiO2(N2) Nanotubes Heterojunction Photoanode for Highly Efficient Photoelectrocatalytic Applications

We report the development of a novel visible response BiVO_4/TiO_2(N_2) nanotubes photoanode for photoelectrocatalytic applications. The nitrogen-treated TiO_2 nanotube shows a high carrier concentration rate, thus resulting in a high efficient charge transportation and low electron–hole recombination in the TiO_2–BiVO_4. Therefore, the BiVO_4/TiO_2(N_2) NTs photoanode enabled with a significantly enhanced photocurrent of 2.73 mA cm^(-2)(at 1 V vs. Ag/Ag Cl) and a degradation efficiency in the oxidation of dyes under visible light. Field emission scanning electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectrometer, and UV–Vis absorption spectrum were conducted to characterize the photoanode and demonstrated the presence of both metal oxides as a junction composite.

Enhanced CH4 yield by photocatalytic CO2 reduction using TiO2 nanotube arrays grafted with Au, Ru, and ZnPd nanoparticles

金属氧化物半导体支持上的金属 nanoparticle (NP ) 合作催化剂为许多化学反应作为光催化剂正在吸引注意。相关努力寻求做并且使用没有磅的催化剂。在这方面，我们报导 25 和 60 摩尔椠 ? 桴 ? 牰獥湥散漠 ? 桴 ? 的这里提高的 CH 4 形成率 ? 獐攠慶畬瑡摥椠 ?

Photo-degradation of Acid-red 3B dye catalyzed by TiO_2 nanotubes

TiO2 nanotube precursor was synthesized by the hydrothermal reaction of TiO2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron microscopic （TEM） observation revealed that the nanotube could be obtained by either a direct rinse with acid solution or rinse with distilled water followed by acid solution. The results of X-ray diffraction （XRD） and inductively coupled plasma （ICP） analysis indicated that the nanotube material was composed of H2Ti2O5·H2O. In addition, the photocatalytic activities of the resulting catalysts were found to be strongly dependent on the post-treatment. The results of the photocatalytic reaction showed that the degradation of Acid-red 3B dye fitted pseudo-zero-order kinetics and TiO2 nanotube prepared under direct rinse with acid solution exhibited a higher catalytic efficiency compared to other catalysts.

TEM Study on the Formation Process of TiO_2 Nanotubes

The process, that the polycrystalline TiO2 powders were converted into TiO2 nanotubes, was observed with transmission electron microscope. The results obtained indicated that in concentrated NaOH aqueous solution, anisotropic swelling appears on the polycrystalline TiO2 granula at first, and then the nanotubes are formed.