Metal-substrate-supported tungsten-oxide nanoarrays via porous-alumina-assisted anodization: from nanocolumns to nanocapsules and nanotubes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F16%3APU119772" target="_blank" >RIV/00216305:26620/16:PU119772 - isvavai.cz</a>

Result on the web

<a href="http://pubs.rsc.org/en/content/articlelanding/2016/ta/c6ta02027e#!divAbstract" target="_blank" >http://pubs.rsc.org/en/content/articlelanding/2016/ta/c6ta02027e#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c6ta02027e" target="_blank" >10.1039/c6ta02027e</a>

Result language

angličtina

Original language name

Metal-substrate-supported tungsten-oxide nanoarrays via porous-alumina-assisted anodization: from nanocolumns to nanocapsules and nanotubes

Original language description

An array of highly aligned tungsten-oxide (TO) nanorods, similar to 80 nm wide, up to 900 nm long, spatially separated at their bottoms by tungsten metal on a substrate is synthesized via the self-localized anodization of aluminum followed by the porous-alumina-assisted re-anodization of tungsten in a sputter-deposited Al/W bilayer. Moreover, the pore-directed TO nanocapsules may grow, which can be electrochemically top-opened in alumina nanopores and transformed to TO nanotubes, representing unique architectures built up on tungsten substrates to date. The as-grown nanorods are composed of amorphous WO3 mixed with minor amounts of WO2 and Al2O3 in the outer layer and oxide-hydroxide compound (WO(3 center dot)nH(2)O) with aluminum tungstate (2Al(2)O(3)center dot 5WO(3)), mainly present inside the rods. Once the growing oxide fills up the pores, it comes out as an array of exotic protuberances of highly hydrated TO, with no analogues among the other valve-metal oxides. Vacuum or air annealing at 550 degrees C increases the portion of non-stoichiometric oxides 'doped' with OH-groups and gives monoclinic WO2.9 or a mixture of WO3 and WO2.9 nanocrystalline phases, respectively. The nanorods show n-type semiconductor behavior when examined by Mott-Schottky analysis, with a high carrier density of 7 x 10(19) or 3 x 10(19) cm(-3) for the air- or vacuum-annealed samples, associated with a charge depletion layer of about 8 or 10 nm, respectively. A model for the growth of the metal-substrate-separated TO nanocapsules and tubes is proposed and experimentally justified. The findings suggest that the new TO nanoarrays with well-defined nano-channels for carriers may form the basic elements for photoanodes or emerging 3-D micro- and nano-sensors.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10405 - Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)

Project

<a href="/en/project/GA14-29531S" target="_blank" >GA14-29531S: Formation and properties of novel self-organized mixed-oxide 3-D nanostructured films for use in advanced microdevices (AnoNanoFilm)</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Materials Chemistry A

ISSN

2050-7488

e-ISSN

2050-7496

Volume of the periodical

21

Issue of the periodical within the volume

4

Country of publishing house

GB - UNITED KINGDOM

Number of pages

14

Pages from-to

8219-8232

UT code for WoS article

000378102400029

EID of the result in the Scopus database

2-s2.0-84981161288