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 language | English |
|---|---|
| Pages (from-to) | 1794-1802 |
| Number of pages | 9 |
| Journal | Energy and Environmental Science |
| Volume | 9 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 1 2016 |
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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 journal › Article
}
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.
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U2 - 10.1039/c5ee03871e
DO - 10.1039/c5ee03871e
M3 - Article
VL - 9
SP - 1794
EP - 1802
JO - Energy and Environmental Science
JF - Energy and Environmental Science
SN - 1754-5692
IS - 5
ER -