APPLICATIONS OF TECHNOLOGY:
- Hydrogen-cooled power plants
- Hydrogen boosting for internal combustion engines
- Small scale, high power applications, e.g., forklift engines
- Fuel cell powered vehicles
- Much lower cost than platinum catalysts
- Earth-abundant material used in lieu of rare platinum
- Works with seawater
- Improves performance of other catalysts
Hydrogen gas derived from water is a carbon neutral and renewable fuel; but to produce it efficiently, the water-splitting electrolysis process requires an expensive catalyst such as platinum. A Berkeley Lab team led by chemists Jeffrey Long and Christopher Chang has discovered a highly effective alternative using low cost and Earth-abundant molybdenum nested within the pocket of a carbon-based molecule.
This laboratory-made molecule mimics a small feature on the chemically active edge of molybdenum disulfide (MoS2), a commonly used industrial catalyst whose natural catalytic properties are likely conferred by the structure of that active site. The researchers have generated a soluble molecular analogue of that site that can potentially be modified further to improve its role in hydrogen production.
In tests, the Berkeley Lab-designed catalyst produced hydrogen gas from mildly acidic water at rates ten- to 100-times higher than with other “molecular” catalysts —catalysts in which metals are bound in organic, carbon-based molecules that can be chemically modified to improve performance. In addition to promoting robust hydrogen production, the Berkeley Lab molybdenum complex remained stable through repeated catalytic cycles. Only trace amounts of it need to be added to water to promote hydrogen production on electrode surfaces. Although the water must be acidic for this process, the presence of contaminants did not affect performance. The catalyst still performed robustly with filtered seawater collected at a San Francisco beach and modified only with acetic acid and sodium acetate to make it more acidic.
The catalytic properties of inorganic crystalline metals such as platinum cannot be improved by synthetic chemistry alone. The Berkeley Lab molecule can be modified in ways that could improve catalysis by changing the metal center, the active catalytic site, or the structure of the organic molecules that bind with the metal to form the complex.
While platinum is currently the best available water-splitting catalyst, it is extremely rare, and Earth-abundant molybdenum is about 74 times less expensive.
DEVELOPMENT STAGE: Proof of principle.
STATUS: Issued U. S. Patents #9,315,909 and #9,499,916. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Yarris, L. “Hydrogen from Acidic Water: Berkeley Lab Researchers Develop a Potential Low Cost Alternative to Platinum for Splitting Water,” Berkeley Lab News Center, February 9, 2012. http://newscenter.lbl.gov/news-releases/2012/02/09/hydrogen-from-acidic-water/
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
REFERENCE NUMBER: JIB-3001