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A Mechanistic Study of the Oxidative Reaction of Hydrogen-Terminated Si(111) Surfaces with Liquid Methanol

Plymale, Noah T. and Dasog, Mita and Brunschwig, Bruce S. and Lewis, Nathan S. (2017) A Mechanistic Study of the Oxidative Reaction of Hydrogen-Terminated Si(111) Surfaces with Liquid Methanol. Journal of Physical Chemistry C, 121 (8). pp. 4270-4282. ISSN 1932-7447. http://resolver.caltech.edu/CaltechAUTHORS:20170125-124627127

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Abstract

H–Si(111) surfaces have been reacted with liquid methanol (CH_3OH) in the absence or presence of a series of oxidants and/or illumination. Oxidant-activated methoxylation of H–Si(111) surfaces was observed in the dark after exposure to CH_3OH solutions that contained the one-electron oxidants acetylferrocenium, ferrocenium, or 1,1’-dimethylferrocenium. The oxidant-activated reactivity toward CH_3OH of intrinsic and n-type H–Si(111) surfaces increased upon exposure to ambient light. The results suggest that oxidant-activated methoxylation requires that two conditions be met: (1) the position of the quasi-Fermi levels must energetically favor oxidation of the H–Si(111) surface and (2) the position of the quasi-Fermi levels must energetically favor reduction of an oxidant in solution. Consistently, illuminated n-type H–Si(111) surfaces underwent methoxylation under applied external bias more rapidly and at more negative potentials than p-type H–Si(111) surfaces. The results under potentiostatic control indicate that only conditions that favor oxidation of the H–Si(111) surface need be met, with charge balance at the surface maintained by current flow at the back of the electrode. The results are described by a mechanistic framework that analyzes the positions of the quasi-Fermi levels relative to the energy levels relevant for each system.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/acs.jpcc.6b11555DOIArticle
http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.6b11555PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/acs.jpcc.6b11555PublisherSupporting Information
ORCID:
AuthorORCID
Plymale, Noah T.0000-0003-2564-8009
Dasog, Mita0000-0002-7846-3414
Brunschwig, Bruce S.0000-0002-6135-6727
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2017 American Chemical Society. Received: November 16, 2016; Revised: January 14, 2017; Published: January 18, 2017. We acknowledge the National Science Foundation grant No. CHE-1214152 for providing support for the materials used in this work. Instrumentation support was provided by the Molecular Materials Research Center of the Beckman Institute at the California Institute of Technology. N.T.P. acknowledges support from a National Science Foundation Graduate Research Fellowship. M.D. acknowledges support from a postdoctoral fellowship from the National Sciences and Engineering Research Council of Canada. N.T.P. and B.S.B acknowledge support from the National Science Foundation CCI Solar Fuels Program under Grant No. CHE-1305124. We thank Dr. Adam C. Nielander for insightful discussions during the preparation of this work.
Group:CCI Solar Fuels
Funders:
Funding AgencyGrant Number
NSFCHE-1214152
NSF Graduate Research FellowshipUNSPECIFIED
National Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
NSFCHE-1305124
Record Number:CaltechAUTHORS:20170125-124627127
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170125-124627127
Official Citation:A Mechanistic Study of the Oxidative Reaction of Hydrogen-Terminated Si(111) Surfaces with Liquid Methanol Noah T. Plymale, Mita Dasog, Bruce S. Brunschwig, and Nathan S. Lewis The Journal of Physical Chemistry C 2017 121 (8), 4270-4282 DOI: 10.1021/acs.jpcc.6b11555
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73721
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Jan 2017 23:50
Last Modified:11 Sep 2017 23:58

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