Limits on the corrosion rate of Si surfaces in contact with CH3OH-ferrocene+/0 and CH3OH-1,1′-dimethylferrocene+/0 solutions

Gary A. Shreve, Chris D. Karp, Katherine E. Pomykal, Nathan S Lewis

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Although Si/CH3OH contacts have been extensively investigated and reported to provide highly efficient photoelectrochemical energy conversion devices, a recent study using the scanning electrochemical microscope (SECM) has claimed that, in CH3OH solutions, Si surfaces in contact with 4.57 mM ferrocenium (Fc+) were etched in the dark at a mass-transport-limited rate. The reported etching rate constant of >0.37 cm s-1 at 4.57 mM ferrocenium corresponds to an equivalent corrosion current density of >240 mA cm-2 and to a Si etch rate of >75 nm s-1. The presence of such severe corrosion was inferred from an unexpectedly large feedback current in an SECM experiment. The present work describes a search for corrosion of Si in contact with CH3OH-ferrocene+/0 and CH3OH-dimethylferrocene(Me2Fc)+/0 solutions through the use of very sensitive electrochemical, chemical, and physical methods. For CH3OH-1.0 M LiClO4-100 mM Me2Fc-80 mM Me2Fc+ solutions, an upper limit on the etch rate of 6.6 × 10-6 nm s-1 has been established through direct experimental measurements; thus, a 400 μm thick Si photoelectrode in contact with the CH3OH-Me2Fc+/0 electrolyte would require over 1500 years to corrode completely at room temperature. An alternative explanation for the SECM data, based on the documented existence of an inversion layer at the Si/liquid contact, is presented and shown to be consistent with the available data.

Original languageEnglish
Pages (from-to)5575-5580
Number of pages6
JournalJournal of Physical Chemistry
Volume99
Issue number15
Publication statusPublished - 1995

Fingerprint

Corrosion rate
Contacts (fluid mechanics)
corrosion
Microscopes
Corrosion
Scanning
microscopes
scanning
Inversion layers
Energy conversion
Electrolytes
Etching
Rate constants
energy conversion
Current density
Mass transfer
Feedback
etching
Liquids
electrolytes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Limits on the corrosion rate of Si surfaces in contact with CH3OH-ferrocene+/0 and CH3OH-1,1′-dimethylferrocene+/0 solutions. / Shreve, Gary A.; Karp, Chris D.; Pomykal, Katherine E.; Lewis, Nathan S.

In: Journal of Physical Chemistry, Vol. 99, No. 15, 1995, p. 5575-5580.

Research output: Contribution to journalArticle

@article{c22ac73b675c49e096fde7be715f6264,
title = "Limits on the corrosion rate of Si surfaces in contact with CH3OH-ferrocene+/0 and CH3OH-1,1′-dimethylferrocene+/0 solutions",
abstract = "Although Si/CH3OH contacts have been extensively investigated and reported to provide highly efficient photoelectrochemical energy conversion devices, a recent study using the scanning electrochemical microscope (SECM) has claimed that, in CH3OH solutions, Si surfaces in contact with 4.57 mM ferrocenium (Fc+) were etched in the dark at a mass-transport-limited rate. The reported etching rate constant of >0.37 cm s-1 at 4.57 mM ferrocenium corresponds to an equivalent corrosion current density of >240 mA cm-2 and to a Si etch rate of >75 nm s-1. The presence of such severe corrosion was inferred from an unexpectedly large feedback current in an SECM experiment. The present work describes a search for corrosion of Si in contact with CH3OH-ferrocene+/0 and CH3OH-dimethylferrocene(Me2Fc)+/0 solutions through the use of very sensitive electrochemical, chemical, and physical methods. For CH3OH-1.0 M LiClO4-100 mM Me2Fc-80 mM Me2Fc+ solutions, an upper limit on the etch rate of 6.6 × 10-6 nm s-1 has been established through direct experimental measurements; thus, a 400 μm thick Si photoelectrode in contact with the CH3OH-Me2Fc+/0 electrolyte would require over 1500 years to corrode completely at room temperature. An alternative explanation for the SECM data, based on the documented existence of an inversion layer at the Si/liquid contact, is presented and shown to be consistent with the available data.",
author = "Shreve, {Gary A.} and Karp, {Chris D.} and Pomykal, {Katherine E.} and Lewis, {Nathan S}",
year = "1995",
language = "English",
volume = "99",
pages = "5575--5580",
journal = "Journal of Physical Chemistry",
issn = "0022-3654",
publisher = "American Chemical Society",
number = "15",

}

TY - JOUR

T1 - Limits on the corrosion rate of Si surfaces in contact with CH3OH-ferrocene+/0 and CH3OH-1,1′-dimethylferrocene+/0 solutions

AU - Shreve, Gary A.

AU - Karp, Chris D.

AU - Pomykal, Katherine E.

AU - Lewis, Nathan S

PY - 1995

Y1 - 1995

N2 - Although Si/CH3OH contacts have been extensively investigated and reported to provide highly efficient photoelectrochemical energy conversion devices, a recent study using the scanning electrochemical microscope (SECM) has claimed that, in CH3OH solutions, Si surfaces in contact with 4.57 mM ferrocenium (Fc+) were etched in the dark at a mass-transport-limited rate. The reported etching rate constant of >0.37 cm s-1 at 4.57 mM ferrocenium corresponds to an equivalent corrosion current density of >240 mA cm-2 and to a Si etch rate of >75 nm s-1. The presence of such severe corrosion was inferred from an unexpectedly large feedback current in an SECM experiment. The present work describes a search for corrosion of Si in contact with CH3OH-ferrocene+/0 and CH3OH-dimethylferrocene(Me2Fc)+/0 solutions through the use of very sensitive electrochemical, chemical, and physical methods. For CH3OH-1.0 M LiClO4-100 mM Me2Fc-80 mM Me2Fc+ solutions, an upper limit on the etch rate of 6.6 × 10-6 nm s-1 has been established through direct experimental measurements; thus, a 400 μm thick Si photoelectrode in contact with the CH3OH-Me2Fc+/0 electrolyte would require over 1500 years to corrode completely at room temperature. An alternative explanation for the SECM data, based on the documented existence of an inversion layer at the Si/liquid contact, is presented and shown to be consistent with the available data.

AB - Although Si/CH3OH contacts have been extensively investigated and reported to provide highly efficient photoelectrochemical energy conversion devices, a recent study using the scanning electrochemical microscope (SECM) has claimed that, in CH3OH solutions, Si surfaces in contact with 4.57 mM ferrocenium (Fc+) were etched in the dark at a mass-transport-limited rate. The reported etching rate constant of >0.37 cm s-1 at 4.57 mM ferrocenium corresponds to an equivalent corrosion current density of >240 mA cm-2 and to a Si etch rate of >75 nm s-1. The presence of such severe corrosion was inferred from an unexpectedly large feedback current in an SECM experiment. The present work describes a search for corrosion of Si in contact with CH3OH-ferrocene+/0 and CH3OH-dimethylferrocene(Me2Fc)+/0 solutions through the use of very sensitive electrochemical, chemical, and physical methods. For CH3OH-1.0 M LiClO4-100 mM Me2Fc-80 mM Me2Fc+ solutions, an upper limit on the etch rate of 6.6 × 10-6 nm s-1 has been established through direct experimental measurements; thus, a 400 μm thick Si photoelectrode in contact with the CH3OH-Me2Fc+/0 electrolyte would require over 1500 years to corrode completely at room temperature. An alternative explanation for the SECM data, based on the documented existence of an inversion layer at the Si/liquid contact, is presented and shown to be consistent with the available data.

UR - http://www.scopus.com/inward/record.url?scp=0001405989&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001405989&partnerID=8YFLogxK

M3 - Article

VL - 99

SP - 5575

EP - 5580

JO - Journal of Physical Chemistry

JF - Journal of Physical Chemistry

SN - 0022-3654

IS - 15

ER -