Researchers from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the University of California, Berkeley have discovered an inexpensive metal catalyst for generating hydrogen from water.
The scientists’ new proton reduction catalyst is made from a molybdenum-oxo metal complex — a material roughly 70 times cheaper than platinum, the metal catalyst most widely used today to split the water molecule.
The importance of the discovery lies in the expectation that hydrogen will be a key ingredient in future renewable energy technologies. The Berkeley researchers’ discovery is a step toward developing an cheap, efficient, carbon-neutral process for generating hydrogen from water.
“Our catalyst does not require organic additives, and can operate in neutral water, even if it is dirty, and can operate in sea water, the most abundant source of hydrogen on earth and a natural electrolyte,” said Hemamala Karunadasa, who discovered the complex along with Christopher Chang and Jeffrey Long. “These qualities make our catalyst ideal for renewable energy and sustainable chemistry.”
The value of hydrogen gas as an electricity-generating fuel is that it emits only water vapor as an exhaust product. Yes, that’s right: you can literally drink what comes out of a hydrogen car’s tailpipe.
There are a few problems with hydrogen gas, however:
- It does not occur naturally and has to be produced.
- Most hydrogen gas in the U.S. today comes from natural gas, a fossil fuel.
- It’s flammable, and must be carefully transported in containers.
- Hydrogen requires an all-new infrastructure to support vehicles.
The best way to produce hydrogen is through electrolysis of water, or using electricity to split molecules of water into molecules of hydrogen and oxygen.
Metal catalysts for this process are commercially available, but they are low valence precious metals with prohibitively high costs. (As mentioned above, platinum is often used, which costs about $2,000 an ounce.)
The researchers’ complex, on the other hand, is a high valence metal that can help generate hydrogen from neutral buffered water or sea water with a turnover frequency of 2.4 moles of hydrogen per mole of catalyst per second.
In other words, sustainable and cheap.
The researchers are currently investigating other, similar metal complexes to facilitate catalytic processes, with a focus on sustainable energy cycles.
Their research is published in the April 29, 2010 issue of the journal Nature.
Image: Jeffrey Long, Christopher Chang and Hemamala Karunadasa; Roy Kaltschmidt/Berkeley Lab Public Affairs
