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TiO2 Nanotube Arrays (tio2 + nanotube_array)
Selected AbstractsMultifunctional Au-Coated TiO2 Nanotube Arrays as Recyclable SERS Substrates for Multifold Organic Pollutants DetectionADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Xuanhua Li Abstract A multifunctional Au-coated TiO2 nanotube array is made via synthesis of a TiO2 nanotube array through a ZnO template, followed by deposition of Au particles onto the TiO2 surface using photocatalytic deposition and a hydrothermal method, respectively. Such arrays exhibit superior detection sensitivity with high reproducibility and stability. In addition, due to possessing stable catalytic properties, the arrays can clean themselves by photocatalytic degradation of target molecules adsorbed to the substrate under irradiation with UV light into inorganic small molecules using surface-enhanced Raman spectroscopy (SERS) detection, so that recycling can be achieved. Finally, by detection of Rhodamine 6G (R6G) dye, herbicide 4-chlorophenol (4-CP), persistent organic pollutant (POP) dichlorophenoxyacetic acid (2,4-D), and organophosphate pesticide methyl-parathion (MP), the unique recyclable properties indicate a new route in eliminating the single-use problem of traditional SERS substrates and show promising applications for detecting other organic pollutants. [source] Nanotube Arrays: Template-Directed Liquid ALD Growth of TiO2 Nanotube Arrays: Properties and Potential in Photovoltaic Devices (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Mater. X. Hu, A. Sellinger, et al. present on page 1390 an array of TiO2 nanotubes prepared via a new liquid atomic layer deposition process in porous anodic alumina templates. The ability to reproduce the arrays on various types of substrates including Si and transparent conducting oxides opens opportunities in many exciting opto-electronic applications. The potential of such arrays in ordered bulk-heterojunction solar cells is explored. [source] Template-Directed Liquid ALD Growth of TiO2 Nanotube Arrays: Properties and Potential in Photovoltaic DevicesADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Thelese R. B. Foong Abstract Dense and well-aligned arrays of TiO2 nanotubes extending from various substrates are successfully fabricated via a new liquid-phase atomic layer deposition (LALD) in nanoporous anodic alumina (AAO) templates followed by alumina dissolution. The facile and versatile process circumvents the need for vacuum conditions critical in traditional gas-phase ALD and yet confers ALD-like deposition rates of 1.6,2.2,Å cycle,1, rendering smooth conformal nanotube walls that surpass those achievable by sol,gel and Ti-anodizing techniques. The nanotube dimensions can be tuned, with most robust structures being 150,400,nm tall, 60,70,nm in diameter with 5,20,nm thick walls. The viability of TiO2 nanotube arrays deposited on indium tin oxide (ITO),glass electrodes for application in model hybrid poly(3-hexylthiophene) (P3HT):TiO2 solar cells is studied. The results achieved provide platforms and research directions for further advancements. [source] Multifunctional Au-Coated TiO2 Nanotube Arrays as Recyclable SERS Substrates for Multifold Organic Pollutants DetectionADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Xuanhua Li Abstract A multifunctional Au-coated TiO2 nanotube array is made via synthesis of a TiO2 nanotube array through a ZnO template, followed by deposition of Au particles onto the TiO2 surface using photocatalytic deposition and a hydrothermal method, respectively. Such arrays exhibit superior detection sensitivity with high reproducibility and stability. In addition, due to possessing stable catalytic properties, the arrays can clean themselves by photocatalytic degradation of target molecules adsorbed to the substrate under irradiation with UV light into inorganic small molecules using surface-enhanced Raman spectroscopy (SERS) detection, so that recycling can be achieved. Finally, by detection of Rhodamine 6G (R6G) dye, herbicide 4-chlorophenol (4-CP), persistent organic pollutant (POP) dichlorophenoxyacetic acid (2,4-D), and organophosphate pesticide methyl-parathion (MP), the unique recyclable properties indicate a new route in eliminating the single-use problem of traditional SERS substrates and show promising applications for detecting other organic pollutants. [source] Electrochemical Method for Synthesis of a ZnFe2O4/TiO2 Composite Nanotube Array Modified Electrode with Enhanced Photoelectrochemical ActivityADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Yang Hou Abstract An electrode with intimate and well-aligned ZnFe2O4/TiO2 composite nanotube arrays is prepared via electrochemical anodization of pure titanium foil in fluorine-containing ethylene glycol, followed by a novel cathodic electrodeposition method. The deposition of ZnFe2O4 is promoted in the self-aligned, vertically oriented TiO2 nanotube arrays but minimized at the tube entrances. Thus, pore clogging is prevented. Environmental scanning electron microscopy, energy-dispersive X-ray spectra, high-resolution transmission electron microscopy, X-ray diffraction patterns, and X-ray photoelectron spectroscopy indicate that the as-prepared samples are highly ordered and vertically aligned TiO2 nanotube arrays with ZnFe2O4 nanoparticles loading. The TiO2 nanotubes are anatase with the preferential orientation of <101> plane. Enhanced absorption in both UV and visible light regions is observed for the composite nanotube arrays. The current,voltage curve of ZnFe2O4 -loaded TiO2 nanotube arrays reveals a rectifying behavior. The enhanced separation of photoinduced electrons and holes is demonstrated by surface photovoltage and photocurrent measurements. Meanwhile, the photoelectrochemical investigations verify that the ZnFe2O4/TiO2 composite nanotube array modified electrode has a more effective photoconversion capability than the aligned TiO2 nanotube arrays alone. In addition, the photoelectrocatalytic ability of the novel electrode is found enhanced in the degradation of 4-chlorophenol. [source] Template-Directed Liquid ALD Growth of TiO2 Nanotube Arrays: Properties and Potential in Photovoltaic DevicesADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Thelese R. B. Foong Abstract Dense and well-aligned arrays of TiO2 nanotubes extending from various substrates are successfully fabricated via a new liquid-phase atomic layer deposition (LALD) in nanoporous anodic alumina (AAO) templates followed by alumina dissolution. The facile and versatile process circumvents the need for vacuum conditions critical in traditional gas-phase ALD and yet confers ALD-like deposition rates of 1.6,2.2,Å cycle,1, rendering smooth conformal nanotube walls that surpass those achievable by sol,gel and Ti-anodizing techniques. The nanotube dimensions can be tuned, with most robust structures being 150,400,nm tall, 60,70,nm in diameter with 5,20,nm thick walls. The viability of TiO2 nanotube arrays deposited on indium tin oxide (ITO),glass electrodes for application in model hybrid poly(3-hexylthiophene) (P3HT):TiO2 solar cells is studied. The results achieved provide platforms and research directions for further advancements. [source] Photosensitization of TiO2 Nanostructures with CdS Quantum Dots: Particulate versus Tubular Support ArchitecturesADVANCED FUNCTIONAL MATERIALS, Issue 5 2009David R. Baker Abstract TiO2 nanotube arrays and particulate films are modified with CdS quantum dots with an aim to tune the response of the photoelectrochemical cell in the visible region. The method of successive ionic layer adsorption and reaction facilitates size control of CdS quantum dots. These CdS nanocrystals, upon excitation with visible light, inject electrons into the TiO2 nanotubes and particles and thus enable their use as photosensitive electrodes. Maximum incident photon to charge carrier efficiency (IPCE) values of 55% and 26% are observed for CdS sensitized TiO2 nanotube and nanoparticulate architectures respectively. The nearly doubling of IPCE observed with the TiO2 nanotube architecture is attributed to the increased efficiency of charge separation and transport of electrons. [source] Synthesis and Photocatalytic Activity of Highly Ordered TiO2 and SrTiO3/TiO2 Nanotube Arrays on Ti SubstratesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Xuming Zhang Highly ordered TiO2 nanotube arrays (TiO2 -NTAs) are produced by electrochemical anodization of a Ti foil in ammonium fluoride (NH4F),ethylene glycol solution. Photocatalytic (PC) investigations indicate that the length of the NTAs plays an important role in their photoactivity. The PC activity increases initially with the NT length and then decreases and the optimum length that yields the highest PC is 6.2 ,m for TiO2 -NTAs. The TiO2 -NTAs are further converted to heterojunction strontium titanate (SrTiO3)/TiO2 -NTAs by a hydrothermal reaction in Sr(OH)2 solution. As the hydrothermal reaction proceeds, more TiO2 is converted into SrTiO3 and the thickness of the SrTiO3 layer increases. The SrTiO3/TiO2 -NTAs exhibit variable PC activities that depend on the hydrothermal reaction time, and the SrTiO3/TiO2 -NTAs hydrothermally treated for 1 h or less have enhanced PC properties. The advantage of combining TiO2 and SrTiO3 stems from the difference in the flatband potential, thereby improving the separation of the photogenerated electron,hole pairs and consequently the PC activity. [source] Electron Field Emission and Photoluminescence of Anatase Nanotube ArraysJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008Yang Yang TiO2 nanotube arrays with a high aspect ratio were grown on conductive Ti substrates by anodization in an organic electrolyte. The as-prepared TiO2 nanotubes were vertically grown and adhered well to the substrates. The photoluminescence spectrum and X-ray diffraction showed that the crystal structure of the postannealed TiO2 nanotube arrays was oxygen-defective anatase. This kind of anatase nanotube arrays exhibited efficient electron field emission even at room temperature with a low applied electric field of ,9 V/,m. The emission current exceeded 70 ,A/cm2 at an extraction voltage of 700 V. [source] Highly defined and ordered top-openings in TiO2 nanotube arraysPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010Sergiu P. Albu Abstract We report a very simple and novel approach to produce anodic TiO2 nanotube arrays with highly defined and ordered tube openings. It is based on carrying out anodization through a slowly soluble photoresist coating. This eliminates the formation of undesired initiation layers on the tube tops and protects them to a certain extent from etching by the electrolyte. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||