Publication detail

Influence of nitrogen species on the porous-alumina-assisted growth of TiO2 nanocolumn arrays

BENDOVÁ, M. KOLÁŘ, J. MÁRIK, M. LEDNICKÝ, T. MOZALEV, A.

Original Title

Influence of nitrogen species on the porous-alumina-assisted growth of TiO2 nanocolumn arrays

Type

journal article in Web of Science

Language

English

Original Abstract

Porous-anodic-alumina (PAA)-assisted anodizing in oxalic acid electrolytes combined with re-anodizing to a more anodic potential of a titanium layer on substrate, followed by chemical dissolution of the PAA overlayer result in TiO2 nanocolumn arrays, which may however be chemically unstable and destroy during the PAA dissolution. Here we show that this is because the TiO2 nanocolumns have easy-todissolve alumina-titania mixed-oxide ‘nanoroots’ penetrating the alumina barrier layer, where gas nano-bubbles and voids form respectively inside and between the titania roots, owing to the fieldassisted crystallization of the bottom titanium oxide. The problem is solved by alloying nitrogen with titanium in the precursor film, with a compositional spread of nitrogen from 2 to 50 at%, to grow differently N-doped TiO2 nanocolumn arrays via the PAA-assisted anodizing in oxalic acid at 40 V followed by re-anodizing up to 240 V. The stability of such arrays increases with increasing nitrogen content, reaching an ideal 100% level for the Tie50 at%N alloy films. The effect is proved to be due to the incorporation of nitrogen into the columns and roots with formation of oxynitride, which increases their chemical resistance and effectively suppresses the field-assisted crystallization of titania, leading to the obstructed O2 evolution, smaller bubbles and voids, less mixing of the two oxides in the roots, and thickening and merging the roots. A model is developed of the oxide growth and dissolution, explaining the instability of the pure TiO2 nanocolumn arrays and defining the stabilizing effect of the nitrogen species. The doping with nitrogen may make the TiO2 nanocolumn arrays highly appropriate for applications to photocatalysis and energy conversion.

Keywords

Anodizing; Titanium oxide; Porous alumina; Nitrogen doping; Nanorods

Authors

BENDOVÁ, M.; KOLÁŘ, J.; MÁRIK, M.; LEDNICKÝ, T.; MOZALEV, A.

Released

10. 8. 2018

ISBN

0013-4686

Periodical

Electrochimica Acta

Year of study

281

Number

1

State

United Kingdom of Great Britain and Northern Ireland

Pages from

796

Pages to

809

Pages count

14

URL

https://www.sciencedirect.com/science/article/pii/S0013468618312659

BibTex

@article{BUT148497,
  author="Mária {Bendová} and Jakub {Kolář} and Marian {Márik} and Tomáš {Lednický} and Alexander {Mozalev}",
  title="Influence of nitrogen species on the porous-alumina-assisted growth of TiO2 nanocolumn arrays",
  journal="Electrochimica Acta",
  year="2018",
  volume="281",
  number="1",
  pages="796--809",
  doi="10.1016/j.electacta.2018.05.197",
  issn="0013-4686",
  url="https://www.sciencedirect.com/science/article/pii/S0013468618312659"
}