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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F18%3APU128242" target="_blank" >RIV/00216305:26620/18:PU128242 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0013468618312659" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0013468618312659</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.electacta.2018.05.197" target="_blank" >10.1016/j.electacta.2018.05.197</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

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

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Electrochimica Acta

ISSN

0013-4686

e-ISSN

1873-3859

Svazek periodika

281

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

14

Strana od-do

796-809

Kód UT WoS článku

000439134600088

EID výsledku v databázi Scopus

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