Hydrogen Evolution from Pt/Ru-Coated p-Type WSe_2 Photocathodes
Abstract
Crystalline p-type WSe_2 has been grown by a chemical vapor transport method. After deposition of noble metal catalysts, p-WSe_2 photocathodes exhibited thermodynamically based photoelectrode energy-conversion efficiencies of >7% for the hydrogen evolution reaction under mildly acidic conditions, and were stable under cathodic conditions for at least 2 h in acidic as well as in alkaline electrolytes. The open circuit potentials of the photoelectrodes in contact with the H^(+)/H_2 redox couple were very close to the bulk recombination/diffusion limit predicted from the Shockley diode equation. Only crystals with a prevalence of surface step edges exhibited a shift in flat-band potential as the pH was varied. Spectral response data indicated effective minority-carrier diffusion lengths of ~1 μm, which limited the attainable photocurrent densities in the samples to ~15 mA cm^(–2) under 100 mW cm^(–2) of Air Mass 1.5G illumination.
Additional Information
© 2012 American Chemical Society. Received: August 29, 2012; published: November 30, 2012. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. The contributions from JRM and HBG were supported by CCSER (the Gordon and Betty Moore Foundation). JRM is supported by a graduate research fellowship from the Office of Science of the U.S. Department of Energy.Attached Files
Published - ja308581g.pdf
Supplemental Material - ja308581g_si_001.pdf
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Additional details
- Eprint ID
- 36773
- Resolver ID
- CaltechAUTHORS:20130205-103231488
- Department of Energy (DOE)
- DE-SC0004993
- Gordon and Betty Moore Foundation
- Created
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2013-02-05Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- JCAP