Protection of hematite photoelectrodes by ALD-TiO2 capping

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F21%3A43923715" target="_blank" >RIV/60461373:22310/21:43923715 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61388955:_____/21:00539266 RIV/60461373:22350/21:43923715 RIV/00216275:25310/21:39918170 RIV/00216305:26620/21:PU140746

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S1010603020309230" target="_blank" >https://www.sciencedirect.com/science/article/pii/S1010603020309230</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jphotochem.2020.113126" target="_blank" >10.1016/j.jphotochem.2020.113126</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Protection of hematite photoelectrodes by ALD-TiO2 capping

Popis výsledku v původním jazyce

Iron (III) oxide, in the form of hematite (α-Fe2O3), is a n-type semiconductor which is photoactive in the visible spectral region. Therefore, use in photoelectrocatalysis and photoassisted water electrolysis may be suggested. For such implementations, stability of contacts with liquid phases is mandatory. Hematite is stable in alkaline media but less stable in acidic media. For the first time the coverage of porous photoactive Sn doped hematite by thin capping layers of TiO2, deposited by Atomic Layer Deposition (ALD) and its impact on photocurrent and chemical stability of hematite is shown. The nominal thicknesses of the TiO2 ALD coatings were 0.5, 2 and 7.5 nm. The presence of the TiO2 coatings was evidenced by X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and scanning TEM coupled with energy dispersive X-ray (EDX) spectroscopy. HR-TEM analyses revealed that the TiO2 capping layers were amorphous and conformal. Exposure of uncovered hematite layers to 1 M sulfuric acid led to a nominal dissolution rate of 0.23 nm/h which was halved when a TiO2 ALD coating (7.5 nm thin) was applied. Due to mismatch of the valence band positions of the two semiconductors, photocurrents were strongly diminished as the capping layer thickness was increased. Post-calcination of as deposited ALD films on hematite resulted in an increase of photocurrent, which only exceeded photocurrents of pristine hematite when the ALD thickness was not more than 0.5 nm. © 2021 Elsevier B.V.

Název v anglickém jazyce

Protection of hematite photoelectrodes by ALD-TiO2 capping

Popis výsledku anglicky

Iron (III) oxide, in the form of hematite (α-Fe2O3), is a n-type semiconductor which is photoactive in the visible spectral region. Therefore, use in photoelectrocatalysis and photoassisted water electrolysis may be suggested. For such implementations, stability of contacts with liquid phases is mandatory. Hematite is stable in alkaline media but less stable in acidic media. For the first time the coverage of porous photoactive Sn doped hematite by thin capping layers of TiO2, deposited by Atomic Layer Deposition (ALD) and its impact on photocurrent and chemical stability of hematite is shown. The nominal thicknesses of the TiO2 ALD coatings were 0.5, 2 and 7.5 nm. The presence of the TiO2 coatings was evidenced by X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and scanning TEM coupled with energy dispersive X-ray (EDX) spectroscopy. HR-TEM analyses revealed that the TiO2 capping layers were amorphous and conformal. Exposure of uncovered hematite layers to 1 M sulfuric acid led to a nominal dissolution rate of 0.23 nm/h which was halved when a TiO2 ALD coating (7.5 nm thin) was applied. Due to mismatch of the valence band positions of the two semiconductors, photocurrents were strongly diminished as the capping layer thickness was increased. Post-calcination of as deposited ALD films on hematite resulted in an increase of photocurrent, which only exceeded photocurrents of pristine hematite when the ALD thickness was not more than 0.5 nm. © 2021 Elsevier B.V.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

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

2021

Kód důvěrnosti údajů

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

Název periodika

Journal of Photochemistry and Photobiology A: Chemistry

ISSN

1010-6030

e-ISSN

—

Svazek periodika

409

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

7

Strana od-do

—

Kód UT WoS článku

000623634700001

EID výsledku v databázi Scopus

2-s2.0-85099693410