Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting

Arto Hiltunen, Tero-Petri Ruoko, Tomi Iivonen, Kimmo Lahtonen, Harri Ali-Löytty, Essi Sarlin, Mika Valden, Markku Leskelä, Nikolai Tkachenko

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.
Original languageEnglish
JournalSustainable Energy & Fuels
Volume2
Issue number9
Pages (from-to)2124-2130
Number of pages7
ISSN2398-4902
DOIs
Publication statusPublished - 1 Sep 2018
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 116 Chemical sciences
  • PHOTOELECTROCHEMICAL CELLS
  • NANOTUBE ARRAYS
  • HEMATITE FILMS
  • OXIDATION
  • TIO2
  • ALPHA-FE2O3
  • PHOTOCURRENT

Cite this

Hiltunen, Arto ; Ruoko, Tero-Petri ; Iivonen, Tomi ; Lahtonen, Kimmo ; Ali-Löytty, Harri ; Sarlin, Essi ; Valden, Mika ; Leskelä, Markku ; Tkachenko, Nikolai. / Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting. In: Sustainable Energy & Fuels. 2018 ; Vol. 2, No. 9. pp. 2124-2130.
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title = "Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting",
abstract = "Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.",
keywords = "116 Chemical sciences, PHOTOELECTROCHEMICAL CELLS, NANOTUBE ARRAYS, HEMATITE FILMS, OXIDATION, TIO2, ALPHA-FE2O3, PHOTOCURRENT",
author = "Arto Hiltunen and Tero-Petri Ruoko and Tomi Iivonen and Kimmo Lahtonen and Harri Ali-L{\"o}ytty and Essi Sarlin and Mika Valden and Markku Leskel{\"a} and Nikolai Tkachenko",
year = "2018",
month = "9",
day = "1",
doi = "10.1039/C8SE00252E",
language = "English",
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journal = "Sustainable Energy & Fuels",
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Hiltunen, A, Ruoko, T-P, Iivonen, T, Lahtonen, K, Ali-Löytty, H, Sarlin, E, Valden, M, Leskelä, M & Tkachenko, N 2018, 'Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting' Sustainable Energy & Fuels, vol. 2, no. 9, pp. 2124-2130. https://doi.org/10.1039/C8SE00252E

Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting. / Hiltunen, Arto; Ruoko, Tero-Petri; Iivonen, Tomi; Lahtonen, Kimmo; Ali-Löytty, Harri; Sarlin, Essi; Valden, Mika; Leskelä, Markku; Tkachenko, Nikolai.

In: Sustainable Energy & Fuels, Vol. 2, No. 9, 01.09.2018, p. 2124-2130.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting

AU - Hiltunen, Arto

AU - Ruoko, Tero-Petri

AU - Iivonen, Tomi

AU - Lahtonen, Kimmo

AU - Ali-Löytty, Harri

AU - Sarlin, Essi

AU - Valden, Mika

AU - Leskelä, Markku

AU - Tkachenko, Nikolai

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.

AB - Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.

KW - 116 Chemical sciences

KW - PHOTOELECTROCHEMICAL CELLS

KW - NANOTUBE ARRAYS

KW - HEMATITE FILMS

KW - OXIDATION

KW - TIO2

KW - ALPHA-FE2O3

KW - PHOTOCURRENT

U2 - 10.1039/C8SE00252E

DO - 10.1039/C8SE00252E

M3 - Article

VL - 2

SP - 2124

EP - 2130

JO - Sustainable Energy & Fuels

JF - Sustainable Energy & Fuels

SN - 2398-4902

IS - 9

ER -