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Hydrogen evolution from Pt/Ru-coated p-type WSe2 photocathodes
James R McKone1, Adam P Pieterick, Harry B Gray
1Division of Chemistry and Chemical Engineering and the Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 East California Blvd, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|December 4, 2012
Summary
Researchers developed p-type tungsten diselenide (WSe2) photocathodes for efficient hydrogen evolution. These WSe2 photoelectrodes achieved over 7% energy conversion efficiency and demonstrated stability in various electrolytes.
Area of Science:
- Materials Science
- Electrochemistry
- Photocatalysis
Background:
- Tungsten diselenide (WSe2) is a promising semiconductor material for photocatalytic applications.
- Developing efficient and stable photocathodes is crucial for hydrogen evolution reactions (HER).
Purpose of the Study:
- To synthesize crystalline p-type WSe2 photocathodes using chemical vapor transport.
- To evaluate the photoelectrochemical performance and stability of WSe2 for HER.
Main Methods:
- Chemical vapor transport (CVT) method for growing p-type WSe2 crystals.
- Deposition of noble metal catalysts on WSe2.
- Photoelectrochemical measurements under simulated solar illumination (Air Mass 1.5G).
Main Results:
- p-WSe2 photocathodes achieved >7% energy conversion efficiency for HER.
- Photocathodes exhibited stability for at least 2 hours in acidic and alkaline electrolytes.
- Open circuit potentials approached the Shockley diode equation limits, indicating efficient charge carrier behavior.
- Minority-carrier diffusion lengths of ~1 μm limited photocurrent densities to ~15 mA cm(-2).
Conclusions:
- Crystalline p-type WSe2 is a viable material for efficient and stable hydrogen evolution photocathodes.
- Further optimization is needed to overcome diffusion length limitations and enhance photocurrent densities.
