Spontaneous Formation of >90% Optically Transmissive, Electrochemically Active CoP Films for Photoelectrochemical Hydrogen Evolution
Abstract
Earth-abundant catalysts for the hydrogen-evolution reaction require increased mass loadings, relative to Pt films, to achieve comparable activity and stability in acidic electrolytes. We report herein that spontaneous nanostructuring of opaque, electrodeposited CoP films, 40–120 nm in thickness, leads to transparent electrocatalyst films that exhibit up to 90% optical transmission in the visible spectrum. The photocurrent density under simulated sunlight at a representative n+p-Si(100)/CoP photocathode increases by 200% after exposure to 0.50 M H₂SO₄ (aq) and remains stable for 12 h of continuous operation. Atomic force microscopy and scanning electron microscopy of the film before and after exposure to 0.50 M H₂SO₄ (aq) validate an optical model for transparent CoP films as probed with spectroscopic ellipsometry.
Additional Information
© 2019 American Chemical Society. Received: October 3, 2019; Accepted: December 2, 2019; Published: December 2, 2019. 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 No. DE-SC0004993. AFM measurements were performed in the Molecular Materials Resource Center, supported by the Beckmann Institute at the California Institute of Technology. We thank T. Tiwald for helpful discussions on models for effective medium approximations and N. Dalleska for assistance with ICP-MS. The authors declare no competing financial interest.Attached Files
Supplemental Material - jz9b02926_si_001.pdf
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Additional details
- Eprint ID
- 100159
- DOI
- 10.1021/acs.jpclett.9b02926
- Resolver ID
- CaltechAUTHORS:20191203-081242656
- Department of Energy (DOE)
- DE-SC0004993
- Caltech Beckman Institute
- Created
-
2019-12-03Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- JCAP