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Issue 21, 2015
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Unassisted HI photoelectrolysis using n-WSe2 solar absorbers

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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.

Graphical abstract: Unassisted HI photoelectrolysis using n-WSe2 solar absorbers

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The article was received on 27 Feb 2015, accepted on 22 Apr 2015 and first published on 27 Apr 2015

Article type: Paper
DOI: 10.1039/C5CP01192B
Author version available: Download Author version (PDF)
Citation: Phys. Chem. Chem. Phys., 2015,17, 13984-13991
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    Unassisted HI photoelectrolysis using n-WSe2 solar absorbers

    J. R. McKone, R. A. Potash, F. J. DiSalvo and H. D. Abruña, Phys. Chem. Chem. Phys., 2015, 17, 13984
    DOI: 10.1039/C5CP01192B

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