The University of Southampton
University of Southampton Institutional Repository

Performance and failure modes of Si anodes patterned with thin-film Ni catalyst islands for water oxidation

Performance and failure modes of Si anodes patterned with thin-film Ni catalyst islands for water oxidation
Performance and failure modes of Si anodes patterned with thin-film Ni catalyst islands for water oxidation
Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable oxygen evolution for over 240 h of continuous operation in 1.0 mol L−1 KOH under simulated sunlight conditions. Buried-junction np+-Si(111) photoanodes with an 18.0% filling fraction of a square array of Ni microelectrodes, np+-Si(111)|NiμE18.0%, demonstrated performance equivalent to a Ni anode in series with a photovoltaic device having an open-circuit voltage of 538 ± 20 mV, a short-circuit current density of 20.4 ± 1.3 mA cm−2, and a photovoltaic efficiency of 6.7 ± 0.9%. For the np+-Si(111)|NiμE18.0% samples, the photocurrent density at the equilibrium potential for oxygen evolution was 12.7 ± 0.9 mA cm−2, yielding an ideal regenerative cell solar-to-oxygen conversion efficiency of 0.47 ± 0.07%. The photocurrent passed exclusively through the Ni catalyst islands to evolve O2 with nearly 100% faradaic efficiency, while a passivating, insulating surface layer of SiOx formed in situ on areas of the Si in direct contact with the electrolyte. The (photo)electrochemical behavior of Si electrodes patterned with varying areal filling fractions of Ni catalyst islands was also investigated. The stability and efficiency of the patterned-catalyst Si electrodes were affected by the filling fraction of the Ni catalyst, the orientation and dopant type of the substrates, and the measurement conditions. The electrochemical behavior at different stages of operation, including Ni catalyst activation, Si passivation, stable operation, and device failure, was affected by the dynamic processes of anodic formation and isotropic dissolution of SiOx on the exposed Si. Ex situ and operando microscopic and spectroscopic studies revealed that these processes were three-dimensional and spatially non-uniform across the surface of the substrate, and occurred near the active catalyst islands. The patterned catalyst/substrate electrodes serve as a model system for accelerated studies of failure mechanisms in photoanodes protected by multifunctional catalytic coatings or other hole-conductive thin-film coatings that contain defects.
983-998
Sun, Ke
13d9d51e-b3f1-43db-83a4-0b6ec16bd899
Ritzert, Nicole l.
9ea00c1b-bb2d-49bd-944f-33ac2f87e93c
John, Jimmy
5dad5446-9e3c-45fd-868e-b7869f9a96b4
Tan, Haiyan
ac5d75e6-dc60-40d4-a6b9-d0f7cf2799ed
Hale, William G.
08ed5dd7-febd-4a58-920a-e5cd4babe792
Jiang, Jingjing
a31776de-b3d8-48c8-92b9-511e8b741b14
Moreno-hernandez, Ivan
b3bd0a7d-d63d-43a6-804a-a9cfe062a15c
Papadantonakis, Kimberly M.
f1c138aa-540e-429a-a0f3-4c9dc8893029
Moffat, Thomas P.
7ad5d8f4-3c71-49e8-a080-3f981996671f
Brunschwig, Bruce S.
9963c670-c36f-476b-83e8-7bba982cbdc6
Lewis, Nathan S.
9b21ed6e-eea1-480f-a4b1-82fcabb6222b
Sun, Ke
13d9d51e-b3f1-43db-83a4-0b6ec16bd899
Ritzert, Nicole l.
9ea00c1b-bb2d-49bd-944f-33ac2f87e93c
John, Jimmy
5dad5446-9e3c-45fd-868e-b7869f9a96b4
Tan, Haiyan
ac5d75e6-dc60-40d4-a6b9-d0f7cf2799ed
Hale, William G.
08ed5dd7-febd-4a58-920a-e5cd4babe792
Jiang, Jingjing
a31776de-b3d8-48c8-92b9-511e8b741b14
Moreno-hernandez, Ivan
b3bd0a7d-d63d-43a6-804a-a9cfe062a15c
Papadantonakis, Kimberly M.
f1c138aa-540e-429a-a0f3-4c9dc8893029
Moffat, Thomas P.
7ad5d8f4-3c71-49e8-a080-3f981996671f
Brunschwig, Bruce S.
9963c670-c36f-476b-83e8-7bba982cbdc6
Lewis, Nathan S.
9b21ed6e-eea1-480f-a4b1-82fcabb6222b

Sun, Ke, Ritzert, Nicole l., John, Jimmy, Tan, Haiyan, Hale, William G., Jiang, Jingjing, Moreno-hernandez, Ivan, Papadantonakis, Kimberly M., Moffat, Thomas P., Brunschwig, Bruce S. and Lewis, Nathan S. (2018) Performance and failure modes of Si anodes patterned with thin-film Ni catalyst islands for water oxidation. Sustainable Energy & Fuels, 2 (5), 983-998. (doi:10.1039/C7SE00583K).

Record type: Article

Abstract

Silicon photoanodes patterned with thin-film Ni catalyst islands exhibited stable oxygen evolution for over 240 h of continuous operation in 1.0 mol L−1 KOH under simulated sunlight conditions. Buried-junction np+-Si(111) photoanodes with an 18.0% filling fraction of a square array of Ni microelectrodes, np+-Si(111)|NiμE18.0%, demonstrated performance equivalent to a Ni anode in series with a photovoltaic device having an open-circuit voltage of 538 ± 20 mV, a short-circuit current density of 20.4 ± 1.3 mA cm−2, and a photovoltaic efficiency of 6.7 ± 0.9%. For the np+-Si(111)|NiμE18.0% samples, the photocurrent density at the equilibrium potential for oxygen evolution was 12.7 ± 0.9 mA cm−2, yielding an ideal regenerative cell solar-to-oxygen conversion efficiency of 0.47 ± 0.07%. The photocurrent passed exclusively through the Ni catalyst islands to evolve O2 with nearly 100% faradaic efficiency, while a passivating, insulating surface layer of SiOx formed in situ on areas of the Si in direct contact with the electrolyte. The (photo)electrochemical behavior of Si electrodes patterned with varying areal filling fractions of Ni catalyst islands was also investigated. The stability and efficiency of the patterned-catalyst Si electrodes were affected by the filling fraction of the Ni catalyst, the orientation and dopant type of the substrates, and the measurement conditions. The electrochemical behavior at different stages of operation, including Ni catalyst activation, Si passivation, stable operation, and device failure, was affected by the dynamic processes of anodic formation and isotropic dissolution of SiOx on the exposed Si. Ex situ and operando microscopic and spectroscopic studies revealed that these processes were three-dimensional and spatially non-uniform across the surface of the substrate, and occurred near the active catalyst islands. The patterned catalyst/substrate electrodes serve as a model system for accelerated studies of failure mechanisms in photoanodes protected by multifunctional catalytic coatings or other hole-conductive thin-film coatings that contain defects.

Full text not available from this repository.

More information

Accepted/In Press date: 3 March 2018
e-pub ahead of print date: 6 March 2018

Identifiers

Local EPrints ID: 421420
URI: http://eprints.soton.ac.uk/id/eprint/421420
PURE UUID: 3c84ebb7-7658-49cb-8d57-4049be41080f

Catalogue record

Date deposited: 11 Jun 2018 16:30
Last modified: 09 Oct 2020 16:36

Export record

Altmetrics

Contributors

Author: Ke Sun
Author: Nicole l. Ritzert
Author: Jimmy John
Author: Haiyan Tan
Author: William G. Hale
Author: Jingjing Jiang
Author: Ivan Moreno-hernandez
Author: Kimberly M. Papadantonakis
Author: Thomas P. Moffat
Author: Bruce S. Brunschwig
Author: Nathan S. Lewis

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×