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Photoelectrochemical water splitting: silicon photocathodes for hydrogen evolution

Warren, Emily L. and Boettcher, Shannon W. and McKone, James R. and Lewis, Nathan S. (2010) Photoelectrochemical water splitting: silicon photocathodes for hydrogen evolution. In: Solar hydrogen and nanotechnology V. Proceedings of SPIE. No.7770. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 77701F. ISBN 978-0-8194-8266-2.

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The development of low cost, scalable, renewable energy technologies is one of today's most pressing scientific challenges. We report on progress towards the development of a photoelectrochemical water-splitting system that will use sunlight and water as the inputs to produce renewable hydrogen with oxygen as a by-product. This system is based on the design principle of incorporating two separate, photosensitive inorganic semiconductor/liquid junctions to collectively generate the 1.7-1.9 V at open circuit needed to support both the oxidation of H_2O (or OH^-) and the reduction of H^+ (or H_2O). Si microwire arrays are a promising photocathode material because the high aspect-ratio electrode architecture allows for the use of low cost, earth-abundant materials without sacrificing energy-conversion efficiency, due to the orthogonalization of light absorption and charge-carrier collection. Additionally, the high surfacearea design of the rod-based semiconductor array inherently lowers the flux of charge carriers over the rod array surface relative to the projected geometric surface of the photoelectrode, thus lowering the photocurrent density at the solid/liquid junction and thereby relaxing the demands on the activity (and cost) of any electrocatalysts. Arrays of Si microwires grown using the Vapor Liquid Solid (VLS) mechanism have been shown to have desirable electronic light absorption properties. We have demonstrated that these arrays can be coated with earth-abundant metallic catalysts and used for photoelectrochemical production of hydrogen. This development is a step towards the demonstration of a complete artificial photosynthetic system, composed of only inexpensive, earth-abundant materials, that is simultaneously efficient, durable, and scalable.

Item Type:Book Section
Related URLs:
URLURL TypeDescription DOIArticle
Warren, Emily L.0000-0001-8568-7881
Boettcher, Shannon W.0000-0001-8971-9123
McKone, James R.0000-0001-6445-7884
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2010 SPIE. We acknowledge Dr. Michael Kelzenberg, Dr. Josh Spurgeon, and Dr. Michael Walter for their contributions. We also thank the members of the NSF Powering the Planet Center for Chemical Innovation for their valuable contributions to this work. We gratefully acknowledge critical support and infrastructure provided for this work by the Kavli Nanoscience Institute at Caltech, the Stanford Global Climate and Energy Project and the U.S. Department of Energy (grant DE-FG02-05ER15754) for financial support.
Group:Kavli Nanoscience Institute
Funding AgencyGrant Number
Kavli Nanoscience InstituteUNSPECIFIED
Stanford Global Climate and Energy Project (GCEP)UNSPECIFIED
Department of Energy (DOE)DE-FG02-05ER15754
Subject Keywords:hydrogen; water-splitting; solar; silicon; photocathode
Series Name:Proceedings of SPIE
Issue or Number:7770
Record Number:CaltechAUTHORS:20110316-132846386
Persistent URL:
Official Citation:Emily L. Warren, Shannon W. Boettcher, James R. McKone and Nathan S. Lewis, "Photoelectrochemical water splitting: silicon photocathodes for hydrogen evolution", Proc. SPIE 7770, 77701F (2010); doi:10.1117/12.860994
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22938
Deposited By: Tony Diaz
Deposited On:16 Mar 2011 22:16
Last Modified:03 Oct 2019 02:41

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