Abstract
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 language | English |
---|---|
Pages (from-to) | 223-231 |
Number of pages | 9 |
Journal | Journal of the American Chemical Society |
Volume | 135 |
Issue number | 1 |
DOIs | |
Publication status | Published - Jan 9 2013 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry