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ABSTRACT: Self-organized, well-crystallized and high aspect-ratio TiO2 nanotube arrays (TNAs) have been prepared by anodic oxidation in dimethyl sulfoxide (DMSO) containing 5wt% HF at 40V (vs.
Pt). A 50h anodization results in a nanotube arrays approximately 19.4μm in length, referred as long tube. As a comparison,
the short titania nanotube arrays, about 500nm in length, was obtained by anodization in HF aqueous solution, referred as
short tube. Different characterization techniques (viz. FESEM, TEM, XRD and DRS) are used to study the nanotubular microstructure.
The morphology of the nanotube electrodes shows an evident influence on their photocatalytic (PC) and photoelectrochemical
reactivity. The long tube reveals enhanced photocurrent response and PC degradation efficiency of organic compounds. The kinetic
constant of PC degradation of methylic orange (MO) for long tube electrode is found 1.55 times as high as the short tube.
A significant photoelectrochemcial synergetic effect in MO degradation was observed on the long tube electrode and the photoelectrocatalytic
(PEC) degradation of MO on long tube is 27% higher than its PC process.
Environmental Chemistry Letters 04/2012; 7(4):363-368. · 1.88 Impact Factor
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Applied Catalysis B: Environmental. 01/2010; 95:408-413.
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ABSTRACT: Highly ordered TiO(2) nanopore arrays (TNPs) electrode was applied as an electrode material for photoelectrochemical (PEC) degradation of methylic orange (MO). As a comparison, the self-organized TiO(2) nanotube arrays (TNAs) electrode about 500 nm in length was fabricated by Ti anodization in 0.5 wt% HF-H(2)O solution. The COD removal rate and color removal rate for PEC degradation of MO using the TNPs electrode was found to be 9 and 7%, respectively, as high as that obtained for TNAs electrode when biased at 0.5 V. The results indicate that the fast electron separation and transport properties of TNPs electrode makes it possesses enhanced PEC performance for the degradation of MO. In addition, the color removal rate of MO by TNPs PEC process increased with increasing bias potential and electrolyte concentration, but decreased with the increasing pH value and initial concentration of the reaction solution.
Water Science & Technology 01/2010; 62(12):2783-9. · 1.12 Impact Factor
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ABSTRACT: The widely utilization of pharmaceutical and personal care products (PPCPs) in the pharmaceutical therapies and agricultural husbandry has led to the worldwide pollution in the environment. In this study, the photoelectrocatalytic (PEC) behaviors of typical PPCPs, tetracycline (TC), were performed via a highly effective TiO(2) nanopore arrays (TNPs) electrode, comparing with electrochemical (EC) and photocatalytic (PC) process. A significant photoelectrochemical synergetic effect in TC degradation was observed on the TNPs electrode and the rate constant for the PEC process of TNPs electrode was approximately 6.7 times as high as its PC process. The TC removal rate achieved approximately 80% within 3h PEC reaction by TNPs electrode, which is approximately 25% higher than that obtained for a conventional coated TiO(2) nanofilm electrode fabricated by sol-gel method. The possible mechanism involved in the PEC degradation of TC by TNPs electrode was discussed. Furthermore, the TNPs electrode also shows enhanced photocurrent response compared with that for the coated TiO(2) nanofilm electrode. Such kind of TiO(2) nanopores will have many potential applications in various areas as an outstanding photoelectrochemical material.
Journal of hazardous materials 07/2009; 171(1-3):678-83. · 4.14 Impact Factor
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ABSTRACT: This work focuses on the experimental studies of a photoelectrocatalytic method for COD determination in a thin-cell reactor based on a highly effective TiO(2) nanotube array electrode. The effect of preparation parameters on the photoelectrocatalytic performance of TiO(2) nanotube array electrodes including the electrolyte, anodic potential, anodic time, solution pH, calcination temperature and time was examined. The TiO(2) nanotube array electrode prepared in preparation parameters at 1% HF electrolyte solution, anodic potential 20V, anodic time 5min, calcination temperature 450 degrees C with highly photoelectrocatalytic performance was chosen as the working electrode. When it is used in a thin-cell photoeletrocatalytic reactor for COD determination, it requires about 1-5min to complete the oxidation of organics without further titration, much faster than the standard K(2)Cr(2)O(7) method (2-4h). It consumes very limited harmless and inexpensive supporting electrolyte, free from secondary pollution. A wide dynamic working range of 0-850mg/L can be achieved by this method, much wider than any other photoeletrocatalytic methods using TiO(2) nanoparticles or nanofilms in the reported literature. The effects of the water components were studied to propose the TiO(2) nanotube array method. Real sample analyses were also carried out and the COD value of real samples determined by this method agreed well with the standard dichromate method, and it shows good accuracy, stability and reproducibility.
Water Research 05/2009; 43(7):1986-92. · 4.86 Impact Factor
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Adv. Mater. 01/2008; 20:1044-1049.
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ABSTRACT: Self-organized and highly ordered titania
nanotube arrays (TNAs) were prepared through electrochemical
anodic oxidization on a titanium foil in 0.5 wt.%
hydrofluoric acid (HF) electrolyte. The current density and
morphology images during the formation process of TNAs
were studied. Results show that the formation of TNAs
includes the following processes. Initially, dense oxide of
titania was rapidly formed on the titanium surface, followed
by small pore formation. The adjacent small pores
were then integrated and become larger pores. At the same
time, small tubes were transformed. These small tubes
were further integrated into larger tubes until the primary
tube formation. Finally, the tubular structure was gradually
optimized and eventually developed into the highly ordered
TNAs. A model was proposed to explain the formation
mechanism of TNAs fabricated on a titanium foil in HF
acid electrolyte.
J. Mater. Sci. 01/2008; 43:1880–1884.
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ABSTRACT: To substitute the non-regular nano-crystalline semiconductor for a novel kind of ordered microstructure is a very important
aspect in the domain of dye-sensitized solar cell. One of the researching hotspots is the highly-ordered TiO2 nanotube architecture. As a new type of titania nano-material, titania nanotube arrays have drawn extraordinary attention
due to its distinctive morphology, notable photoelectrical and hydro-sensitive performance. At 100% sun the new kind of TiO2 nanotube arrays solar cell exhibits an overall conversion efficiency of 5.44%. This paper introduces the preparation methods
of titania nanotube arrays, the existing problems and recent progress in titania nanotube arrays solar cell.
Chinese Science Bulletin 05/2007; 52(12):1585-1589. · 1.32 Impact Factor
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ABSTRACT: The short, robust and highly ordered TiO2 nanotube arrays (TNAs) electrode was prepared by sonoelectrochemical anodization of titanium in HF–H2O electrolyte solution (referred as short TNAs, STNAs). The self-organized arrays of titania nanotubes of approximately 12–65 nm in diameter and 75–280 nm in length can be synthesized at anodic voltage of 5–20 V. The electron transport process within the STNAs electrode was much favorable in comparison with that for the long TNAs electrode synthesized by conventional magnetic agitation technique (referred as long TNAs, LTNAs), as confirmed by the obviously enhanced photocurrent response of STNAs electrode either in 0.02 M Na2SO4 electrolyte solution or in different concentrations of glucose solution or under different intensities of UV illumination. To investigate their photoelectrochemical applications, degradation of tetracycline, a typical pharmaceutical and personal care products (PPCPs), was carried out using photoelectrocatalytic (PEC) means, comparing with electrochemical (EC) and photocatalytic (PC) processes. The kinetic constant of the PEC process of STNAs electrode was ∼3.17 times as high as its PC process. The color removal rate of tetracycline by STNAs electrode achieved 81% within 3 h, which was 21% higher than that for LTNAs electrode. In degrading tetracycline, 41% of TOC was mineralized using the STNAs electrode against 23% using LTNAs electrode under similar conditions. Such kind of titania nanotubes will have many potential applications in various areas as an outstanding photoelectrochemical material.
Applied Catalysis B: Environmental.
