Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation

Jennifer Leduc; Yakup Goenuellue; Pedram Ghamgosar; Shujie You; Johanne Mouzon; Heechae Choi; Alberto Vomiero; Matthias Grosch; Sanjay Mathur

doi:10.1021/acsanm.8b01936

Electronically-Coupled Phase Boundaries in α-Fe₂O₃/Fe₃O₄ Nanocomposite Photoanodes for Enhanced Water Oxidation

Jennifer Leduc, Yakup Goenuellue, Pedram Ghamgosar, Shujie You, Johanne Mouzon, Heechae Choi, Alberto Vomiero, Matthias Grosch, Sanjay Mathur^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

34 Citations (Scopus)

Abstract

Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of α-Fe₂O₃/Fe₃O₄ composite films via a single-step chemical vapor deposition of [Fe(O^tBu)₃]₂ and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm² at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm²) standard illumination was found for hybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe₂O₃/Fe₃O₄ nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe₂O₃) and ferrimagnetic (Fe₃O₄) oxides, which in view of their differential chemical constitution and valence states of Fe ions (Fe²⁺/Fe³⁺) can enhance the charge separation and thus the overall electrical conductivity of the layer.

Original language	English
Pages (from-to)	334-342
Number of pages	9
Journal	ACS Applied Nano Materials
Volume	2
Issue number	1
DOIs	https://doi.org/10.1021/acsanm.8b01936
Publication status	Published - 25 Jan 2019
Externally published	Yes

Keywords

Raman
heterostructures
magnetite
single-source CVD
solar water splitting
valence dynamics

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1021/acsanm.8b01936

Cite this

@article{73a1a003871e4260a388bfbd5a47907f,

title = "Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation",

abstract = "Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of α-Fe2O3/Fe3O4 composite films via a single-step chemical vapor deposition of [Fe(OtBu)3]2 and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm2 at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm2) standard illumination was found for hybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe2O3) and ferrimagnetic (Fe3O4) oxides, which in view of their differential chemical constitution and valence states of Fe ions (Fe2+/Fe3+) can enhance the charge separation and thus the overall electrical conductivity of the layer.",

keywords = "Raman, heterostructures, magnetite, single-source CVD, solar water splitting, valence dynamics",

author = "Jennifer Leduc and Yakup Goenuellue and Pedram Ghamgosar and Shujie You and Johanne Mouzon and Heechae Choi and Alberto Vomiero and Matthias Grosch and Sanjay Mathur",

note = "Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

year = "2019",

month = jan,

day = "25",

doi = "10.1021/acsanm.8b01936",

language = "English",

volume = "2",

pages = "334--342",

journal = "ACS Applied Nano Materials",

issn = "2574-0970",

number = "1",

}

TY - JOUR

T1 - Electronically-Coupled Phase Boundaries in α-Fe2O3/Fe3O4 Nanocomposite Photoanodes for Enhanced Water Oxidation

AU - Leduc, Jennifer

AU - Goenuellue, Yakup

AU - Ghamgosar, Pedram

AU - You, Shujie

AU - Mouzon, Johanne

AU - Choi, Heechae

AU - Vomiero, Alberto

AU - Grosch, Matthias

AU - Mathur, Sanjay

PY - 2019/1/25

Y1 - 2019/1/25

N2 - Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of α-Fe2O3/Fe3O4 composite films via a single-step chemical vapor deposition of [Fe(OtBu)3]2 and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm2 at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm2) standard illumination was found for hybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe2O3) and ferrimagnetic (Fe3O4) oxides, which in view of their differential chemical constitution and valence states of Fe ions (Fe2+/Fe3+) can enhance the charge separation and thus the overall electrical conductivity of the layer.

AB - Photoelectrochemical (PEC) water splitting reactions are promising for sustainable hydrogen production from renewable sources. We report here, the preparation of α-Fe2O3/Fe3O4 composite films via a single-step chemical vapor deposition of [Fe(OtBu)3]2 and their use as efficient photoanode materials in PEC setups. Film thickness and phase segregation was controlled by varying the deposition time and corroborated through cross-section Raman spectroscopy and scanning electron microscopy. The highest water oxidation activity (0.48 mA/cm2 at 1.23 V vs RHE) using intermittent AM 1.5 G (100 mW/cm2) standard illumination was found for hybrid films with a thickness of 11 μm. This phenomenon is attributed to an improved electron transport resulting from a higher magnetite content toward the substrate interface and an increased light absorption due to the hematite layer mainly located at the top surface of the film. The observed high efficiency of α-Fe2O3/Fe3O4 nanocomposite photoanodes is attributed to the close proximity and establishment of 3D interfaces between the weakly ferro- (Fe2O3) and ferrimagnetic (Fe3O4) oxides, which in view of their differential chemical constitution and valence states of Fe ions (Fe2+/Fe3+) can enhance the charge separation and thus the overall electrical conductivity of the layer.

KW - Raman

KW - heterostructures

KW - magnetite

KW - single-source CVD

KW - solar water splitting

KW - valence dynamics

UR - http://www.scopus.com/inward/record.url?scp=85065245957&partnerID=8YFLogxK

U2 - 10.1021/acsanm.8b01936

DO - 10.1021/acsanm.8b01936

M3 - Article

AN - SCOPUS:85065245957

SN - 2574-0970

VL - 2

SP - 334

EP - 342

JO - ACS Applied Nano Materials

JF - ACS Applied Nano Materials

IS - 1

ER -