Formation of self-organized niobium porous oxide on niobium

Sieber, I.; Hildebrand, H.; Friedrich, A.; Schmuki, Patrik

doi:10.1016/j.elecom.2004.11.012

Cited by 300 publications

(199 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.…”

mentioning

confidence: 99%

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

Zhou

Nguyen

Özkan

et al. 2014

Electrochemistry Communications

169

138

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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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mentioning

confidence: 99%

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

Zhou

Nguyen

Özkan

et al. 2014

Electrochemistry Communications

169

138

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“…Taking into account the results of the above investigations as well as other works concerned with Al, Ti, and Nb anodization [3,10,43,46,47], one can suggest a general scheme leading to the formation of oxide nanotubes on the metal surface. A steady state must be reached for the process in which oxide formation is nearly compensated by oxide dissolution.…”

Section: Discussionmentioning

confidence: 65%

“…The pores showed an irregular morphology with a diameter equal to approximately 50 nm and layer thickness up to 40 μm after 5 h of anodization. The formation of smooth and straight nanotubes was achieved in the subsequent work [43], in which 1 M (NH 4 ) 2 SO 4 +0.5 wt% NH 4 F with pH=5.3 electrolyte was used under a constant potential of 20 V. Further investigations showed [30] that the potential sweep rate from the OCP to anodizing potential can be an important factor to fabricate self-organized nanotube layers. From the results of the above investigations, it can be deduced that fluoride ions in the solution are necessary to induce competing chemical dissolution of the oxide, while the morphology and the structure of the deposit can be influenced by pH, electrolyte composition, and imposed potential.…”

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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“…3 Furthermore, during the last years, it was shown that also other valve metals, such as Zr [15][16][17] and Nb [18,19], and several Ti binary [20][21][22], ternary [23,24] and quaternary alloys [25,26] can be anodized to nanotubular or nanoporous structures in fluoride containing electrolytes. The nanotubes grown on these alloys are similar to pure TiO 2 nanotubes.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Self-organized double-wall oxide nanotube layers on glass-forming Ti-Zr-Si(-Nb) alloys

Sopha

Pohl

Damm

et al. 2017

Materials Science and Engineering: C

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In this work, we report for the first time on the use of melt spun glass-forming alloysTi 75 Zr 10 Si 15 (TZS) and Ti 60 Zr 10 Si 15 Nb 15 (TZSN) -as substrates for the growth of anodic oxide nanotube layers. Upon their anodization in ethylene glycol based electrolytes, highly ordered nanotube layers were achieved. In comparison to TiO 2 nanotube layers grown on Ti foils, under the same conditions for reference, smaller diameter nanotubes (~116 nm for TZS and ~90 nm for TZSN) and shorter nanotubes (~11.5 µm and ~6.5 µm for TZS and TZSN, respectively) were obtained for both amorphous alloys. Furthermore, TEM and STEM studies, coupled with EDX analysis, revealed a double-wall structure of the as-grown amorphous oxide nanotubes with Ti species being enriched in the inner wall, and Si species in the outer wall, whereby Zr and Nb species were homogeneously distributed.

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Formation of self-organized niobium porous oxide on niobium

Cited by 300 publications

References 20 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

Self-organized double-wall oxide nanotube layers on glass-forming Ti-Zr-Si(-Nb) alloys

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