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Title: Unassisted HI photoelectrolysis using n-WSe 2 solar absorbers

Abstract

Molybdenum and tungsten diselenide are among the most robust and efficient semiconductor materials for photoelectrochemistry, but they have seen limited use for integrated solar energy storage systems. Herein, we report that n-type WSe 2 photoelectrodes can facilitate unassisted aqueous HI electrolysis to H 2(g) and HI 3(aq) when placed in contact with a platinum counter electrode and illuminated by simulated sunlight. Even in strongly acidic electrolyte, the photoelectrodes are robust and operate very near their maximum power point. We have rationalized this behavior by characterizing the n-WSe 2|HI/HI 3 half cell, the Pt|HI/H 2||HI 3/HI|Pt full cell, and the n-WSe 2 band-edge positions. Importantly, specific interactions between the n-WSe 2 surface and aqueous iodide significantly shift the semiconductor’s flatband potential and allow for unassisted HI electrolysis. These findings exemplify the important role of interfacial chemical reactivity in influencing the energetics of semiconductor-liquid junctions and the resulting device performance.

Authors:
 [1];  [1];  [1];  [1]
  1. Department of Chemistry and Chemical Biology; Cornell University; Ithaca, USA
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Energy Materials Center at Cornell (EMC2)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1370464
DOE Contract Number:
SC0001086
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 17; Journal Issue: 21; Related Information: Emc2 partners with Cornell University (lead); Lawrence Berkeley National Laboratory
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

McKone, James R., Potash, Rebecca A., DiSalvo, Francis J., and Abruña, Héctor D. Unassisted HI photoelectrolysis using n-WSe 2 solar absorbers. United States: N. p., 2015. Web. doi:10.1039/c5cp01192b.
McKone, James R., Potash, Rebecca A., DiSalvo, Francis J., & Abruña, Héctor D. Unassisted HI photoelectrolysis using n-WSe 2 solar absorbers. United States. doi:10.1039/c5cp01192b.
McKone, James R., Potash, Rebecca A., DiSalvo, Francis J., and Abruña, Héctor D. Thu . "Unassisted HI photoelectrolysis using n-WSe 2 solar absorbers". United States. doi:10.1039/c5cp01192b.
@article{osti_1370464,
title = {Unassisted HI photoelectrolysis using n-WSe 2 solar absorbers},
author = {McKone, James R. and Potash, Rebecca A. and DiSalvo, Francis J. and Abruña, Héctor D.},
abstractNote = {Molybdenum and tungsten diselenide are among the most robust and efficient semiconductor materials for photoelectrochemistry, but they have seen limited use for integrated solar energy storage systems. Herein, we report that n-type WSe2 photoelectrodes can facilitate unassisted aqueous HI electrolysis to H2(g) and HI3(aq) when placed in contact with a platinum counter electrode and illuminated by simulated sunlight. Even in strongly acidic electrolyte, the photoelectrodes are robust and operate very near their maximum power point. We have rationalized this behavior by characterizing the n-WSe2|HI/HI3 half cell, the Pt|HI/H2||HI3/HI|Pt full cell, and the n-WSe2 band-edge positions. Importantly, specific interactions between the n-WSe2 surface and aqueous iodide significantly shift the semiconductor’s flatband potential and allow for unassisted HI electrolysis. These findings exemplify the important role of interfacial chemical reactivity in influencing the energetics of semiconductor-liquid junctions and the resulting device performance.},
doi = {10.1039/c5cp01192b},
journal = {Physical Chemistry Chemical Physics. PCCP (Print)},
number = 21,
volume = 17,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}