Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation

Wei Li, Da He, Stafford W. Sheehan, Yumin He, James E. Thorne, Xiahui Yao, Gary W Brudvig, Dunwei Wang

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Photoelectrochemical (PEC) reactions, such as water splitting, promise a direct route for solar-to-chemical energy conversion. Successful implementations of these reactions often require the combination of catalysts with photoelectrodes. How these catalysts improve the performance of photoelectrodes, however, is not well understood, making it difficult to further improve these systems for practical applications. Here, we present a systematic study that directly compares two water-oxidation catalysts (WOCs) on a hematite (α-Fe2O3)-based PEC system. We observe that when a thin layer of a heterogenized molecular Ir catalyst (het-WOC) is applied to a hematite photoanode, the system's performance is improved primarily due to improved charge transfer (>2 fold), while the surface recombination rate remains unchanged. In stark contrast, heterogeneous oxide catalysts (IrOx) improve the PEC performance of hematite by significantly reducing the surface recombination rate. These results suggest that the het-WOC provides additional charge-transfer pathways across the Fe2O3H2O interface, while IrOx and similar bulk metal-oxide catalysts replace the Fe2O3H2O interface with a fundamentally different one.

Original languageEnglish
Pages (from-to)1794-1802
Number of pages9
JournalEnergy and Environmental Science
Volume9
Issue number5
DOIs
Publication statusPublished - May 1 2016

Fingerprint

Oxides
catalyst
oxide
oxidation
Oxidation
Catalysts
Water
Hematite
hematite
water
recombination
Charge transfer
comparison
Energy conversion
Metals
fold
ferric oxide

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Environmental Chemistry
  • Pollution
  • Nuclear Energy and Engineering

Cite this

Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation. / Li, Wei; He, Da; Sheehan, Stafford W.; He, Yumin; Thorne, James E.; Yao, Xiahui; Brudvig, Gary W; Wang, Dunwei.

In: Energy and Environmental Science, Vol. 9, No. 5, 01.05.2016, p. 1794-1802.

Research output: Contribution to journalArticle

Li, Wei ; He, Da ; Sheehan, Stafford W. ; He, Yumin ; Thorne, James E. ; Yao, Xiahui ; Brudvig, Gary W ; Wang, Dunwei. / Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation. In: Energy and Environmental Science. 2016 ; Vol. 9, No. 5. pp. 1794-1802.
@article{52dab78f63da45439bf05bce6d9ba45b,
title = "Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation",
abstract = "Photoelectrochemical (PEC) reactions, such as water splitting, promise a direct route for solar-to-chemical energy conversion. Successful implementations of these reactions often require the combination of catalysts with photoelectrodes. How these catalysts improve the performance of photoelectrodes, however, is not well understood, making it difficult to further improve these systems for practical applications. Here, we present a systematic study that directly compares two water-oxidation catalysts (WOCs) on a hematite (α-Fe2O3)-based PEC system. We observe that when a thin layer of a heterogenized molecular Ir catalyst (het-WOC) is applied to a hematite photoanode, the system's performance is improved primarily due to improved charge transfer (>2 fold), while the surface recombination rate remains unchanged. In stark contrast, heterogeneous oxide catalysts (IrOx) improve the PEC performance of hematite by significantly reducing the surface recombination rate. These results suggest that the het-WOC provides additional charge-transfer pathways across the Fe2O3H2O interface, while IrOx and similar bulk metal-oxide catalysts replace the Fe2O3H2O interface with a fundamentally different one.",
author = "Wei Li and Da He and Sheehan, {Stafford W.} and Yumin He and Thorne, {James E.} and Xiahui Yao and Brudvig, {Gary W} and Dunwei Wang",
year = "2016",
month = "5",
day = "1",
doi = "10.1039/c5ee03871e",
language = "English",
volume = "9",
pages = "1794--1802",
journal = "Energy and Environmental Science",
issn = "1754-5692",
publisher = "Royal Society of Chemistry",
number = "5",

}

TY - JOUR

T1 - Comparison of heterogenized molecular and heterogeneous oxide catalysts for photoelectrochemical water oxidation

AU - Li, Wei

AU - He, Da

AU - Sheehan, Stafford W.

AU - He, Yumin

AU - Thorne, James E.

AU - Yao, Xiahui

AU - Brudvig, Gary W

AU - Wang, Dunwei

PY - 2016/5/1

Y1 - 2016/5/1

N2 - Photoelectrochemical (PEC) reactions, such as water splitting, promise a direct route for solar-to-chemical energy conversion. Successful implementations of these reactions often require the combination of catalysts with photoelectrodes. How these catalysts improve the performance of photoelectrodes, however, is not well understood, making it difficult to further improve these systems for practical applications. Here, we present a systematic study that directly compares two water-oxidation catalysts (WOCs) on a hematite (α-Fe2O3)-based PEC system. We observe that when a thin layer of a heterogenized molecular Ir catalyst (het-WOC) is applied to a hematite photoanode, the system's performance is improved primarily due to improved charge transfer (>2 fold), while the surface recombination rate remains unchanged. In stark contrast, heterogeneous oxide catalysts (IrOx) improve the PEC performance of hematite by significantly reducing the surface recombination rate. These results suggest that the het-WOC provides additional charge-transfer pathways across the Fe2O3H2O interface, while IrOx and similar bulk metal-oxide catalysts replace the Fe2O3H2O interface with a fundamentally different one.

AB - Photoelectrochemical (PEC) reactions, such as water splitting, promise a direct route for solar-to-chemical energy conversion. Successful implementations of these reactions often require the combination of catalysts with photoelectrodes. How these catalysts improve the performance of photoelectrodes, however, is not well understood, making it difficult to further improve these systems for practical applications. Here, we present a systematic study that directly compares two water-oxidation catalysts (WOCs) on a hematite (α-Fe2O3)-based PEC system. We observe that when a thin layer of a heterogenized molecular Ir catalyst (het-WOC) is applied to a hematite photoanode, the system's performance is improved primarily due to improved charge transfer (>2 fold), while the surface recombination rate remains unchanged. In stark contrast, heterogeneous oxide catalysts (IrOx) improve the PEC performance of hematite by significantly reducing the surface recombination rate. These results suggest that the het-WOC provides additional charge-transfer pathways across the Fe2O3H2O interface, while IrOx and similar bulk metal-oxide catalysts replace the Fe2O3H2O interface with a fundamentally different one.

UR - http://www.scopus.com/inward/record.url?scp=84970983949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84970983949&partnerID=8YFLogxK

U2 - 10.1039/c5ee03871e

DO - 10.1039/c5ee03871e

M3 - Article

AN - SCOPUS:84970983949

VL - 9

SP - 1794

EP - 1802

JO - Energy and Environmental Science

JF - Energy and Environmental Science

SN - 1754-5692

IS - 5

ER -