Hydrogen evolution from Pt/Ru-coated p-type WSe2 photocathodes

James R. McKone, Adam P. Pieterick, Harry B. Gray, Nathan S. Lewis

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145 Citations (Scopus)


Crystalline p-type WSe2 has been grown by a chemical vapor transport method. After deposition of noble metal catalysts, p-WSe2 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+/H2 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.

Original languageEnglish
Pages (from-to)223-231
Number of pages9
JournalJournal of the American Chemical Society
Issue number1
Publication statusPublished - Jan 9 2013

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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