Formation of hexagonally ordered nanoporous anodic zirconia

Berger, Steffen; Jakubka, Florian; Schmuki, Patrik

doi:10.1016/j.elecom.2008.10.002

Cited by 90 publications

(62 citation statements)

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“…It should be noted though that the as-formed tubes are amorphous and contain significant amount of fluorides and typically carbon, and for many applications need to be thermally crystallized to anatase or mixed anatase/rutile structures [46]. Furthermore, it is worth mentioning that using dilute fluoride electrolytes, similar aligned oxide tubes or pore-morphologies can be grown on a full range of other metals (Zr [47][48][49], Hf [50], Ta [51][52][53], Fe [54][55][56], Nb [57,58], Co [59], V [60]) and many alloys, see e.g. ref.…”

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confidence: 99%

Anodic TiO2 nanotube layers: Why does self-organized growth occur—A mini review

Zhou

Nguyen

Özkan

et al. 2014

Electrochemistry Communications

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The present review gives an overview of the highlights of more than 10 years of research on synthesis and applications of ordered oxide structures (nanotube layers, hexagonal pore arrangements) that are formed by self-organizing anodization of metals. In particular we address the questions after the critical factors that lead to the spectacular self-ordering during the growth of anodic oxides that finally yield morphologies such as highly ordered TiO 2 nanotube arrays and similar structures. Why are tubes and pores formed -what are the key parameters controlling these processes?Link to the published article: http://dx.doi.org/10.1016/j.elecom.2014.06.021 1 Over the past decade, the formation and application of anodic, self-organized TiO 2 nanotube arrays grown from a Ti metal (as illustrated in Fig.1) and similar oxide structures have attracted wide scientific and technological interest [1][2][3][4][5][6][7]. Self-organization during anodization has been observed already more than 70 years ago for aluminum that, when anodized in acidic electrolytes, forms hexagonally ordered porous structures [8] -such ordering can peak in a virtually perfect arrangement, as demonstrated by Masuda et al. in 1995 [9], by a meticulous optimization of the electrochemical growth conditions. These alumina structures since then have been widely used for templating (i.e., to fill the pores by a secondary material to form nanorods or nanowires, in combination with stripping the template or not), as well as for numerous other applications -excellent overviews on growth and applications of porous alumina are available; see e.g. refs. [2][3][4]10,11].In the past few years, however, research activities on ordered TiO 2 nanotube layers have in numbers of paper-output surpassed porous alumina; in the past decade, more than three thousand papers have been published dedicated to anodic TiO 2 nanotubes [1,[5][6][7]. The main reason for this enormous interest is the anticipated impact of such nanotube layers in functional applications of titanium dioxide; such as dye sensitized solar cells [12][13][14][15], photocatalysis [16,17] (including water splitting for the generation of hydrogen, pollution degradation, or the reduction of CO 2 ), biomedicine [18][19][20] (biomedical coatings of implants, drug delivery systems), ion-insertion batteries, electrochromics, etc. [21][22][23][24] These applications are, to a large extent, based on a number of almost unique features of TiO 2 [1,[25][26][27][28]: it is a semiconductor of a band-gap of 3.0 eV (rutile) -3.2 eV (anatase), with a considerably large electron diffusion length (mainly anatase), relative band-edge positions suitable to trigger a wide range of photocatalytic reactions; the material is highly biocompatible, and shows considerably good ion intercalation properties. Many of these features can be exploited in a nanotubular form even more beneficially than in powder assemblies (e.g. directional charge transport, orthogonal carrier separation, optimized and directional diffusion profile...

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confidence: 99%

Anodic TiO2 nanotube layers: Why does self-organized growth occur—A mini review

Zhou

Nguyen

Özkan

et al. 2014

Electrochemistry Communications

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168

138

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“…It has already been reported that using the organic additives such as glycerol or ethylene glycol will usually either increase the thickness of the layer or change the order of its structure [27,28,44]. Berger et al [5,44] used ethylene glycol/ glycerol-based electrolyte added to NH 4 F aqueous solution and observed a significant increase of the oxide layer thickness.…”

Section: Discussionmentioning

confidence: 99%

“…Berger et al [5,44] used ethylene glycol/ glycerol-based electrolyte added to NH 4 F aqueous solution and observed a significant increase of the oxide layer thickness. Moreover, by varying the water addition, they managed to demonstrate the switch between porous and tubular morphology.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of ZrO2 nanotubes in inorganic and organic electrolytes by anodic oxidation of zirconium

Stępień

Handzlik

Fitzner

2014

J Solid State Electrochem

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Present work reports on the results of the electrochemical growth of self-ordered zirconia nanotubes formed in aqueous Na 2 SO 4 +HF and nonaqueous electrolytes with glycerol addition. Anodization process was carried out in this inorganic water-based mixture with constant pH=2.5 and in the voltage range from 5 to 60 V. Similar experiments were repeated in an organic glycerol-based electrolyte with the voltage equal to 20 V and with variable glycerol concentration. All experiments were conducted at constant room temperature. The tube diameter dependence on the voltage of anodization process in an inorganic electrolyte was derived. It was found that when glycerol addition to water electrolyte was used, it takes more time to produce long zirconia nanotubes. However, they do not collapse as the similar structure of the same length formed in aqueous electrolyte.

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“…Based on successful application of anodic aluminum oxide in various applications, other valve metals such as Ti, Nb, W, Hf have been intensively studied for the last decade [2][3][4][5][6][7]. Especially, due to unique chemical and physical properties of TiO2 such as biocompatibility, semiconductor, and catalytic effects, anodization technique of Ti has been developed to produce various morphological features according to expansion of applications.…”

Section: Introduction 1)mentioning

confidence: 99%

Research Trends in Doping Methods on TiO<sub>2</sub> Nanotube Arrays Prepared by Electrochemical Anodization

Yoo¹,

Choi²

2015

Applied Chemistry for Engineering

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Nanotubular TiO2 prepared by electrochemical anodization has been significantly used for various applications due to high aspect ratio structures showing a high chemical stability. Morphological properties of nanotubular titanium oxide are easily tailored by adjusting types and compositions of electrolyte, pH value, applied voltage, temperature and anodization time. Since their catalytic properties can be enhanced by doping foreign elements into TiO2, metal as well as non-metal elements are doped into TiO2 nanotubes using different methods. For example, single anodization, thermal annealing, precipitation, and electrochemical deposition have been applied to simplify the doping process. In this review, anodization of Ti to produce TiO2 and doping methods will be discussed in detail.

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Formation of hexagonally ordered nanoporous anodic zirconia

Cited by 90 publications

References 31 publications

Anodic TiO2 nanotube layers: Why does self-organized growth occur—A mini review

Anodic TiO2 nanotube layers: Why does self-organized growth occur—A mini review

Synthesis of ZrO2 nanotubes in inorganic and organic electrolytes by anodic oxidation of zirconium

Research Trends in Doping Methods on TiO<sub>2</sub> Nanotube Arrays Prepared by Electrochemical Anodization

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