A novel titanium dioxide (TiO2) film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium. The local electric field at the anodized surface was simulated and i...A novel titanium dioxide (TiO2) film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium. The local electric field at the anodized surface was simulated and its influence on the morphology of the TiO2 film was discussed. The results show that the electric field strength is enhanced by the covering. The growth rate of TiO2 increases with the assist of the local electric field. However, TiO2 dissolution is hindered since the local electric field prevents [TiF6]6- from diffusing. It means that the balance condition for the formation of nanotubes is broken, and TiO2 nanoparticles are formed. Moreover, the crystal structure of the TiO2 film was confirmed using X-ray diffraction and Raman analysis. The anatase is a main phase for the proposed film.展开更多
Titanium dioxide (TiO<sub>2</sub>) doped with neodymium (Nd) and/or Gadolinium (Gd) rare-earth elements were fabricated into nanotubes via the hydrothermal method in a KOH solution and in-situ doping. Tita...Titanium dioxide (TiO<sub>2</sub>) doped with neodymium (Nd) and/or Gadolinium (Gd) rare-earth elements were fabricated into nanotubes via the hydrothermal method in a KOH solution and in-situ doping. Titanium dioxide nanotubes (TNTs) and in-situ Nd-doped and/or Gd-doped TNTs were characterized with transmission and scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Morphologies indicated a network of aggregated nanotubes. The phase and composition analyses revealed that the lanthanide TNTs had anatase phases with Nd and/or Gd nanoparticles in the TNT lattice. The nanoparticles were uniformly deposited on the surface because of hydroxyl groups on the TNT surfaces, resulting in a very high loading density. The outer diameter and the length of the TNTs increased with doping. The mechanisms for the formation of multiwall TNTs are discussed.展开更多
Two-dimensional (2D) ultrathin MoS2-modified black Ti^3+-TiO2 nanotubes were fabricated using an electrospinning-hydrothermal treatment-reduction method.Bare TiO2 nanotubes were fabricated via electrospinning.Then,2D ...Two-dimensional (2D) ultrathin MoS2-modified black Ti^3+-TiO2 nanotubes were fabricated using an electrospinning-hydrothermal treatment-reduction method.Bare TiO2 nanotubes were fabricated via electrospinning.Then,2D MoS2 lamellae were grown on the surface of the nanotubes and Ti^3+/Ov ions were introduced by reduction.The photocatalytic performance of the 2D MoS2/Ti^3+-TiO2 nanotubes was^15 times better than that of TiO2.The HER enhancement of the MoS2/Ti^3+-TiO2 nanotubes can be attributed to the Pt-like behavior of 2D MoS2 and the presence of Ti^3+-ions,which facilitated the quick diffusion of the photogenerated electrons to water,reducing the H2 activation barrier.The presence of Ov ions in the nanotubes and their hollow structure increased their solar utilization.展开更多
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, an...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.展开更多
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 mi...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.展开更多
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 re...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.展开更多
IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and character...IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.展开更多
Polyaniline (PANI) composite nanotubes (90-130 nm in diameter) containing titanium dioxide (TiO2) nanoparticles (about 10 nm in diameter) were synthesized through a self-assembly process in the presence of a-n...Polyaniline (PANI) composite nanotubes (90-130 nm in diameter) containing titanium dioxide (TiO2) nanoparticles (about 10 nm in diameter) were synthesized through a self-assembly process in the presence of a-naphthalenesulfonic acid (a-NSA) as the dopant. It was found that PANI-TiO2 composites and PANI nanotubes both behaved with significant photocatalytic activities towards AZO dyes, during 2 h photocatalytic processes under natural light, the degradation ratio was 94.2% and 97.2% respectively (methyl orange and orange II). The morphology of such products was characterized by SEM. The specific surface area of such composite nanotubes was 14.7 m2/g compared to normal polyaniline which was 0.27 m2/g. IR and X-ray diffraction characterizations showed that the chemical chain of the composite nanotubes was identical to that of the doped PANI. It may provide a new way for photodegradation of organic contaminants by using conjugated polymer with dimensional structure.展开更多
We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To impro...We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To improve the energy transfer efficiency,UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2matrix.β‐NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)core–shell nanoparticles were used as nanotransducers for near infrared light.These nanoparticles exhibited enhanced upconversion fluorescence compared withβ‐NaYF4:Yb(30%),Tm(0.5%)orβ–NaYF4:Yb(30%),Tm(0.5%)@NaYF4nanoparticles.The morphologies,size and chemical compositions have been extensively investigated using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),X‐ray diffraction(XRD)and X‐ray photoelectron spectra(XPS),respectively.The TEM images showed that the TiO2composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles.The composite TiO2nanotubes degraded more than90%of rhodamine B(RhB)dye during20min of irradiation by simulated solar light.In particular,more than50%of RhB was decomposed in70min,under irradiation of near infrared light(NIR).This high degradation was attributed to the full spectrum absorption of solar light,and the enhanced transfer efficiency for near infrared light.The as‐prepared nanostructures can harness solar energy,and provide an alternative to overcome energy shortages and environmental protection.展开更多
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 electrochemi...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.展开更多
The platinum nanoparticles supported on self-organized TiO2 nanotubes (Pt-TiO2/Ti) were prepared using electrochemical anodic oxidation followed by cathodic reduction. The structure and chemical nature of the Pt-TiO...The platinum nanoparticles supported on self-organized TiO2 nanotubes (Pt-TiO2/Ti) were prepared using electrochemical anodic oxidation followed by cathodic reduction. The structure and chemical nature of the Pt-TiO2/Ti electrocatalyst were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both XRD and SEM results indicate the presence of platinum on nanotubular TiO2. The stability of the Pt deposits was also investigated in 0.5 mol/L H2SO4 solution by cyclic voltammetry. The electrocatalytic activity of the Pt-TiO2/Ti catalyst exhibits enhancement effect during electro-oxidation of methanol when annealed to anatase. Successive cyclic voltam- mograms of methanol oxidation on the Pt-TiO2/Ti electrocatalyst shows unique electrocatalytic characteristics when compared to methanol oxidation on the bulk Pt catalyst. This is because of further quick oxidation of adsorbed CO by Pt (111) facets of Pt particles on self-organized TiO2 nanotubes when the formation of an electroactive film onto the working catalyst surface occurs.展开更多
A bi-layer photoanode for dye-sensitized solar cell(DSSC) was fabricated, in which TiO_2 hollow spheres(THSs) were designed as a scattering layer and P25/multi-walled carbon nanotubes(MWNTs) as an under-layer. The THS...A bi-layer photoanode for dye-sensitized solar cell(DSSC) was fabricated, in which TiO_2 hollow spheres(THSs) were designed as a scattering layer and P25/multi-walled carbon nanotubes(MWNTs) as an under-layer. The THSs were synthesized by a sacrifice template method and showed good light scattering ability as an over-layer of the photoanode. MWNTs were mixed with P25 to form an under-layer of the photoanode to improve the electron transmission ability of the photoanode. The power conversion efficiency of this kind of DSSC with bi-layer was enhanced to 5.13 %,which is 14.25 % higher than that of pure P25 DSSC.Graphical Abstract A bi-layer composite photoanode based on P25/MWNTs-THSs with improved light scattering and electron transmission, which will provide a new insight into fabrication and structure design of highly efficient dyesensitized solar cells.展开更多
TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,w...TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.展开更多
An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with using thin films of TiO2 nanotubes and nanoparticles as an efficient c...An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with using thin films of TiO2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO2 thin films with different thickness values are fabricated. Two cells use layers of TiO2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol-gel synthesized TiO2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO2 nanotubes grow in length the series resistance (Rs) between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.展开更多
A novel method was developed for the sensitive determination of nickel in environmental water samples by using TiO2 nanotubes, a new nanomaterial, as solid phase extraction absorbent. In general, TiO2 nanomaterials we...A novel method was developed for the sensitive determination of nickel in environmental water samples by using TiO2 nanotubes, a new nanomaterial, as solid phase extraction absorbent. In general, TiO2 nanomaterials were often used for catalytic degradation of pollutants in environmental field, and only a very few application in environmental analytic chemistry. In present work, TiO2 nanotubes was firstly used for the enrichment of nickel and the factors would influence the preconcentration performance were optimized. Under the optimal conditions, TiO2 nanotubes exhibited its good enrichment capacity for nickel and the detection limit of the proposed method was 1 ng· mL^-1. The proposed method was validated with real water samples, and excellent results were obtained with the spiked recoveries in the range of 94.4-99.2%, respectively.展开更多
The influence of calcination temperature on TiO2 nanotubes' catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes (TNTs) were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as T...The influence of calcination temperature on TiO2 nanotubes' catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes (TNTs) were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature's influence on TNTs' adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand (COD) and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.展开更多
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 process...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.展开更多
We report the in vitro cell test and in vivo animal test results of titanium oxide nanotubes (TiO2 NTs) as a potential therapeutic agent used for cancer thermotherapy in combination with near-infrared (NIR) laser. The...We report the in vitro cell test and in vivo animal test results of titanium oxide nanotubes (TiO2 NTs) as a potential therapeutic agent used for cancer thermotherapy in combination with near-infrared (NIR) laser. The in vitro cell test results show that both the cells exposed to NIR laser without TiO2 NTs treatment and the cells treated with TiO2 NTs but not with NIR irradiation had cell viabilities higher than 96%. Combination of these two techniques, however, shows cell viability less than 1%. The cell death rate strongly depended on the concentration of TiO2 NTs. Also, the cell deaths were mostly due to necrosis but partly due to late apoptosis. The in vivo animal test results show that tumor cells can be completely destroyed without nearly giving damage to surrounding healthy cells by an injection of an adequate amount of TiO2 NTs/NaCl suspension and a subsequent single continuous laser treatment at a moderately low laser illumina-tion intensity for the exposure time optimized for the tumor size. These results suggest that TiO2 NTs can be effectively utilized as a therapeutic agent for cancer thermotherapy due to their excellent photothermal property and high bio-compatibility.展开更多
The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,...The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,which posed a challenge to the conventional techniques. In this work,the batch experiments on TC adsorption in aqueous solution of hydrogel( HG) consisting of graphene oxide( GO) and TiO_2 nanotubes( TN) were successfully conducted. HG composite( HG-TN-GO) was prepared with TN and GO with self-assembly method during the oxidation-reduction reaction,and criogel( CG) with TN and GO was characterized by pH at point of zero charge( pH_(pzc)), transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy( XPS). The adsorption capacity of HG-TN-GO on TC was evaluated by analyzing its isotherms. The maximum adsorption capacity reached 751. 3 mg/g. Besides,the adsorption isotherms were well fitted by the Langmuir model, with the theoretical maximum( q_m) of 797. 0 mg/g. The adsorption process was systematically studied by varying pH during the whole adsorption process. The adsorption occurred probably via π-π interaction and cation-π bonding between TC and the HG-TN-GO surface. The composite could be regenerated in 50% ethanol aqueous solution,without significant capacity loss. After 6 recycles,the decrease of adsorption capacity was less than 10%.展开更多
A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO2 nanotubes (TiO2 NTs) was fulfilled with the aim of improving bioactivity of Ti implant.First,well-ordered TiO2 NTs were prepared by t...A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO2 nanotubes (TiO2 NTs) was fulfilled with the aim of improving bioactivity of Ti implant.First,well-ordered TiO2 NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH4F and 10 wt% H2O at 20 V for 50 min,followed by annealing.Then,the carboxylated CNTs were coated onto the TiO2 NTs using electrophoretic deposition (EPD) technique.The growth of hydroxyapatite (HA) on the samples was investigated by soaking them in simulated body fluid (SBF).The result showed the CNTs-coated Ti with the modification of TiO2 NTs (CNTs-TiO2 NTs) was more efficient to induce HA formation than the CNTs-coated smooth Ti (CNTs-Ti).The vitro cell response was evaluated using osteoblast cells (MC3T3-E1).The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO2 NTs.These results indicated that CNT coating on the Ti modified with TiO2 NTs could be potentially useful for the periodontal ligament combination on dental implants.展开更多
文摘A novel titanium dioxide (TiO2) film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium. The local electric field at the anodized surface was simulated and its influence on the morphology of the TiO2 film was discussed. The results show that the electric field strength is enhanced by the covering. The growth rate of TiO2 increases with the assist of the local electric field. However, TiO2 dissolution is hindered since the local electric field prevents [TiF6]6- from diffusing. It means that the balance condition for the formation of nanotubes is broken, and TiO2 nanoparticles are formed. Moreover, the crystal structure of the TiO2 film was confirmed using X-ray diffraction and Raman analysis. The anatase is a main phase for the proposed film.
文摘Titanium dioxide (TiO<sub>2</sub>) doped with neodymium (Nd) and/or Gadolinium (Gd) rare-earth elements were fabricated into nanotubes via the hydrothermal method in a KOH solution and in-situ doping. Titanium dioxide nanotubes (TNTs) and in-situ Nd-doped and/or Gd-doped TNTs were characterized with transmission and scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Morphologies indicated a network of aggregated nanotubes. The phase and composition analyses revealed that the lanthanide TNTs had anatase phases with Nd and/or Gd nanoparticles in the TNT lattice. The nanoparticles were uniformly deposited on the surface because of hydroxyl groups on the TNT surfaces, resulting in a very high loading density. The outer diameter and the length of the TNTs increased with doping. The mechanisms for the formation of multiwall TNTs are discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.51672249,51802282,and 11804301)the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LQ17F040004 and LY17E020001)Fundamental Research Funds of Zhejiang Sci-Tech University(No.2019Q062)。
文摘Two-dimensional (2D) ultrathin MoS2-modified black Ti^3+-TiO2 nanotubes were fabricated using an electrospinning-hydrothermal treatment-reduction method.Bare TiO2 nanotubes were fabricated via electrospinning.Then,2D MoS2 lamellae were grown on the surface of the nanotubes and Ti^3+/Ov ions were introduced by reduction.The photocatalytic performance of the 2D MoS2/Ti^3+-TiO2 nanotubes was^15 times better than that of TiO2.The HER enhancement of the MoS2/Ti^3+-TiO2 nanotubes can be attributed to the Pt-like behavior of 2D MoS2 and the presence of Ti^3+-ions,which facilitated the quick diffusion of the photogenerated electrons to water,reducing the H2 activation barrier.The presence of Ov ions in the nanotubes and their hollow structure increased their solar utilization.
基金This project was supported by the National Natural Science Foundation of China (20071010).
文摘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.
文摘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.
基金the National Nature Science Foundation of China(21507085,21576162)Shanghai Sailing Program of China(14YF1401500)for financial support
文摘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.
文摘IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.
基金Funded in Part by the Research Fund of Hubei Provincial Department of Education,China(No.Q20121102)
文摘Polyaniline (PANI) composite nanotubes (90-130 nm in diameter) containing titanium dioxide (TiO2) nanoparticles (about 10 nm in diameter) were synthesized through a self-assembly process in the presence of a-naphthalenesulfonic acid (a-NSA) as the dopant. It was found that PANI-TiO2 composites and PANI nanotubes both behaved with significant photocatalytic activities towards AZO dyes, during 2 h photocatalytic processes under natural light, the degradation ratio was 94.2% and 97.2% respectively (methyl orange and orange II). The morphology of such products was characterized by SEM. The specific surface area of such composite nanotubes was 14.7 m2/g compared to normal polyaniline which was 0.27 m2/g. IR and X-ray diffraction characterizations showed that the chemical chain of the composite nanotubes was identical to that of the doped PANI. It may provide a new way for photodegradation of organic contaminants by using conjugated polymer with dimensional structure.
基金supported in part by the National Natural Science Foundation of China(21471043,21304028,51403195,31501576)~~
文摘We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To improve the energy transfer efficiency,UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2matrix.β‐NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)core–shell nanoparticles were used as nanotransducers for near infrared light.These nanoparticles exhibited enhanced upconversion fluorescence compared withβ‐NaYF4:Yb(30%),Tm(0.5%)orβ–NaYF4:Yb(30%),Tm(0.5%)@NaYF4nanoparticles.The morphologies,size and chemical compositions have been extensively investigated using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),X‐ray diffraction(XRD)and X‐ray photoelectron spectra(XPS),respectively.The TEM images showed that the TiO2composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles.The composite TiO2nanotubes degraded more than90%of rhodamine B(RhB)dye during20min of irradiation by simulated solar light.In particular,more than50%of RhB was decomposed in70min,under irradiation of near infrared light(NIR).This high degradation was attributed to the full spectrum absorption of solar light,and the enhanced transfer efficiency for near infrared light.The as‐prepared nanostructures can harness solar energy,and provide an alternative to overcome energy shortages and environmental protection.
基金the financial support provided by internal reseach funding of Khalifa University of Science and Technology,United Arab Emirates(Grant No.CIRA-2018-16)。
文摘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.
基金the 11th Five-Year Supporting Programs of Science and Technology (No. 2006BAD04A12)
文摘The platinum nanoparticles supported on self-organized TiO2 nanotubes (Pt-TiO2/Ti) were prepared using electrochemical anodic oxidation followed by cathodic reduction. The structure and chemical nature of the Pt-TiO2/Ti electrocatalyst were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both XRD and SEM results indicate the presence of platinum on nanotubular TiO2. The stability of the Pt deposits was also investigated in 0.5 mol/L H2SO4 solution by cyclic voltammetry. The electrocatalytic activity of the Pt-TiO2/Ti catalyst exhibits enhancement effect during electro-oxidation of methanol when annealed to anatase. Successive cyclic voltam- mograms of methanol oxidation on the Pt-TiO2/Ti electrocatalyst shows unique electrocatalytic characteristics when compared to methanol oxidation on the bulk Pt catalyst. This is because of further quick oxidation of adsorbed CO by Pt (111) facets of Pt particles on self-organized TiO2 nanotubes when the formation of an electroactive film onto the working catalyst surface occurs.
基金the support provided by the National High Technology Research and Development Program 863 (No.2006AA05Z417)Science and Technology Platform Construction Project of Dalian (2010-354)+4 种基金the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning (No.2013-70)‘‘Shu Guang’’ project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (No.13SG55)National Natural Science Foundation of China (NSFC) (No.61376009)Science and Technology Commission of Shanghai Municipality (No.14YF1410500)Shanghai Young Teacher Supporting Foundation (No.ZZEGD14011)
文摘A bi-layer photoanode for dye-sensitized solar cell(DSSC) was fabricated, in which TiO_2 hollow spheres(THSs) were designed as a scattering layer and P25/multi-walled carbon nanotubes(MWNTs) as an under-layer. The THSs were synthesized by a sacrifice template method and showed good light scattering ability as an over-layer of the photoanode. MWNTs were mixed with P25 to form an under-layer of the photoanode to improve the electron transmission ability of the photoanode. The power conversion efficiency of this kind of DSSC with bi-layer was enhanced to 5.13 %,which is 14.25 % higher than that of pure P25 DSSC.Graphical Abstract A bi-layer composite photoanode based on P25/MWNTs-THSs with improved light scattering and electron transmission, which will provide a new insight into fabrication and structure design of highly efficient dyesensitized solar cells.
基金financially supported by the National R&D Program of China under No.2017YFA0207400National Key Research and Development Plan under No.2016YFA0300801National Natural Science Foundation of China under Nos.51502033,61571079,61131005 and 51572042
文摘TiO_2 nanotubes(TNTs) have drawn tremendous attention owing to their unique architectural and physical properties. Anodizing of titanium foil has proven to be the most efficient method to fabricate well-aligned TNTs,which, however, usually produces amorphous TNTs and needs further thermal annealing. Recently, a water-assisted crystallization strategy has been proposed and investigated by both science and engineering communities. This method is very efficient and energy saving, and it circumvents the drawbacks of thermal sintering approach. In this paper, we review the recent research progress in this kind of lowtemperature crystallization approach. Here, various synthetic methods are summarized, and the mechanisms of the amorphous–crystalline transformation are analyzed. The fundamental properties and applications of the low-temperature products are also discussed. Furthermore, it is proved that the water-assisted crystallization approach is not only applicable to TNTs but also to crystallizing other metal oxides.
文摘An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with using thin films of TiO2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO2 thin films with different thickness values are fabricated. Two cells use layers of TiO2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol-gel synthesized TiO2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO2 nanotubes grow in length the series resistance (Rs) between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.
基金the Creative Talented Person's Fund of Henan Province (No.[2005]126)Natural Science Foundation of Henan Province(No.072300460010)+1 种基金the Fund of Henan Normal University (No.2006PL06)the grants from the Henan Key Laboratory for environmental pollution control.
文摘A novel method was developed for the sensitive determination of nickel in environmental water samples by using TiO2 nanotubes, a new nanomaterial, as solid phase extraction absorbent. In general, TiO2 nanomaterials were often used for catalytic degradation of pollutants in environmental field, and only a very few application in environmental analytic chemistry. In present work, TiO2 nanotubes was firstly used for the enrichment of nickel and the factors would influence the preconcentration performance were optimized. Under the optimal conditions, TiO2 nanotubes exhibited its good enrichment capacity for nickel and the detection limit of the proposed method was 1 ng· mL^-1. The proposed method was validated with real water samples, and excellent results were obtained with the spiked recoveries in the range of 94.4-99.2%, respectively.
基金Supported by Tianjin Science and Technology Development Plan Project (No.06YFGZSH06700)
文摘The influence of calcination temperature on TiO2 nanotubes' catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes (TNTs) were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature's influence on TNTs' adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand (COD) and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.
基金financially supported by the National Key Project on Basic Research(No.2013CB933203)the Natural Science Foundation of China(Nos.21373224 and 21577143)+1 种基金the Natural Science Foundation of Fujian Province(Nos.2014H0054 and 2015J0544)the One Hundred Talents Program of the Chinese Academy of Sciences
文摘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.
文摘We report the in vitro cell test and in vivo animal test results of titanium oxide nanotubes (TiO2 NTs) as a potential therapeutic agent used for cancer thermotherapy in combination with near-infrared (NIR) laser. The in vitro cell test results show that both the cells exposed to NIR laser without TiO2 NTs treatment and the cells treated with TiO2 NTs but not with NIR irradiation had cell viabilities higher than 96%. Combination of these two techniques, however, shows cell viability less than 1%. The cell death rate strongly depended on the concentration of TiO2 NTs. Also, the cell deaths were mostly due to necrosis but partly due to late apoptosis. The in vivo animal test results show that tumor cells can be completely destroyed without nearly giving damage to surrounding healthy cells by an injection of an adequate amount of TiO2 NTs/NaCl suspension and a subsequent single continuous laser treatment at a moderately low laser illumina-tion intensity for the exposure time optimized for the tumor size. These results suggest that TiO2 NTs can be effectively utilized as a therapeutic agent for cancer thermotherapy due to their excellent photothermal property and high bio-compatibility.
基金Environmental Engineering,Natural Science Foundation of China(No.51522805)Innovation Foundation of Nanjing Institute of Technology,China(No.CKJB201410)
文摘The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,which posed a challenge to the conventional techniques. In this work,the batch experiments on TC adsorption in aqueous solution of hydrogel( HG) consisting of graphene oxide( GO) and TiO_2 nanotubes( TN) were successfully conducted. HG composite( HG-TN-GO) was prepared with TN and GO with self-assembly method during the oxidation-reduction reaction,and criogel( CG) with TN and GO was characterized by pH at point of zero charge( pH_(pzc)), transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy( XPS). The adsorption capacity of HG-TN-GO on TC was evaluated by analyzing its isotherms. The maximum adsorption capacity reached 751. 3 mg/g. Besides,the adsorption isotherms were well fitted by the Langmuir model, with the theoretical maximum( q_m) of 797. 0 mg/g. The adsorption process was systematically studied by varying pH during the whole adsorption process. The adsorption occurred probably via π-π interaction and cation-π bonding between TC and the HG-TN-GO surface. The composite could be regenerated in 50% ethanol aqueous solution,without significant capacity loss. After 6 recycles,the decrease of adsorption capacity was less than 10%.
基金Funded by the Ministry of Knowledge Economy (MKE) of Korea(No.2010-H-004-00020000-2010)the Ministry of Education of Korea(No.2010-0023901)
文摘A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO2 nanotubes (TiO2 NTs) was fulfilled with the aim of improving bioactivity of Ti implant.First,well-ordered TiO2 NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH4F and 10 wt% H2O at 20 V for 50 min,followed by annealing.Then,the carboxylated CNTs were coated onto the TiO2 NTs using electrophoretic deposition (EPD) technique.The growth of hydroxyapatite (HA) on the samples was investigated by soaking them in simulated body fluid (SBF).The result showed the CNTs-coated Ti with the modification of TiO2 NTs (CNTs-TiO2 NTs) was more efficient to induce HA formation than the CNTs-coated smooth Ti (CNTs-Ti).The vitro cell response was evaluated using osteoblast cells (MC3T3-E1).The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO2 NTs.These results indicated that CNT coating on the Ti modified with TiO2 NTs could be potentially useful for the periodontal ligament combination on dental implants.