A paper published in Nature on Apr. 29, 2010, reported the discovery of a efficient, carbon-neutral catalyst for producing hydrogen from water that is 70 times cheaper than platinum, which is the current standard, the Lawrence Berkeley National Laboratory announced last week.[1]  --  Popular Science commented on Tuesday:  "The research is still preliminary and the Berkeley team is just getting into some of the more exciting chemistry.  They're looking for additional similar metals that might generate hydrogen gas at even higher efficiency, so by the time this kind of tech is commercialized we may have found an even better catalyst.  In the meantime, Mo-oxo marks a sort of corner-turning for water electrolysis."[2] ...


1.

News release

BERKELEY SCIENTISTS DISCOVER INEXPENSIVE METAL CATALYST FOR GENERATING HYDROGEN FROM WATER

By Lynn Yarris (510-486-5375; This email address is being protected from spambots. You need JavaScript enabled to view it.)

Berkeley Lab (Lawrence Berkeley National Laboratory)
April 30, 2010

http://newscenter.lbl.gov/news-releases/2010/04/30/inexpensive-catalyst-for-generating-hydrogen-from-water/

Hydrogen would command a key role in future renewable energy technologies, experts agree, if a relatively cheap, efficient, and carbon-neutral means of producing it can be developed.  An important step towards this elusive goal has been taken by a team of researchers with the U.S. Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley.  The team has discovered an inexpensive metal catalyst that can effectively generate hydrogen gas from water.

“Our new proton reduction catalyst is based on a molybdenum-oxo metal complex that is about 70 times cheaper than platinum, today’s most widely used metal catalyst for splitting the water molecule,” said Hemamala Karunadasa, one of the co-discoverers of this complex.  “In addition, 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.  These qualities make our catalyst ideal for renewable energy and sustainable chemistry.”

Karunadasa holds joint appointments with Berkeley Lab’s Chemical Sciences Division and U.C. Berkeley’s Chemistry Department.  She is the lead author of a paper describing this work that appears in the April 29, 2010 issue of the journal *Nature*, titled “A molecular molybdenum-oxo catalyst for generating hydrogen from water.” Co-authors of this paper were Christopher Chang and Jeffrey Long, who also hold joint appointments with Berkeley Lab and UC Berkeley. Chang, in addition, is also an investigator with the Howard Hughes Medical Institute (HHMI).

Hydrogen gas, whether combusted or used in fuel cells to generate electricity, emits only water vapor as an exhaust product, which is why this nation would already be rolling towards a hydrogen economy if only there were hydrogen wells to tap.  However, hydrogen gas does not occur naturally and has to be produced.  Most of the hydrogen gas in the United States today comes from natural gas, a fossil fuel.  While inexpensive, this technique adds huge volumes of carbon emissions to the atmosphere.  Hydrogen can also be produced through the electrolysis of water -- using electricity to split molecules of water into molecules of hydrogen and oxygen.  This is an environmentally clean and sustainable method of production -- especially if the electricity is generated via a renewable technology such as solar or wind -- but requires a water-splitting catalyst.

Nature has developed extremely efficient water-splitting enzymes -- called hydrogenases -- for use by plants during photosynthesis, however, these enzymes are highly unstable and easily deactivated when removed from their native environment.  Human activities demand a stable metal catalyst that can operate under non-biological settings.

Metal catalysts are commercially available, but they are low valence precious metals whose high costs make their widespread use prohibitive.  For example, platinum, the best of them, costs some $2,000 an ounce.

“The basic scientific challenge has been to create earth-abundant molecular systems that produce hydrogen from water with high catalytic activity and stability,” Chang says.  “We believe our discovery of a molecular molybdenum-oxo catalyst for generating hydrogen from water without the use of additional acids or organic co-solvents establishes a new chemical paradigm for creating reduction catalysts that are highly active and robust in aqueous media.”

The molybdenum-oxo complex that Karunadasa, Chang and Long discovered is a high valence metal with the chemical name of (PY5Me2)Mo-oxo. In their studies, the research team found that this complex catalyzes the generation of hydrogen from neutral buffered water or even sea water with a turnover frequency of 2.4 moles of hydrogen per mole of catalyst per second.

Long says, “This metal-oxo complex represents a distinct molecular motif for reduction catalysis that has high activity and stability in water.  We are now focused on modifying the PY5Me ligand portion of the complex and investigating other metal complexes based on similar ligand platforms to further facilitate electrical charge-driven as well as light-driven catalytic processes.  Our particular emphasis is on chemistry relevant to sustainable energy cycles.”

This research was supported in part by the DOE Office of Science through Berkeley Lab’s Helios Solar Energy Research Center, and in part by a grant from the National science Foundation.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our website at http://www.lbl.gov.

Additional Information

For more about the research of Christopher Chang, visit the Website at http://www.cchem.berkeley.edu/cjcgrp/

For more about the research of Jeffrey Long, visit the Website at http://alchemy.cchem.berkeley.edu/

2.

CHEAP NEW METAL CATALYST CAN SPLIT HYDROGEN GAS FROM WATER AT A FRACTION OF THE COST

By Clay Dillow

Popular Science
May 3, 2010

http://www.popsci.com/science/article/2010-05/cheap-metal-catalyst-can-split-hydrogen-gas-water-fraction-cost

Hydrogen is the most abundant element in the universe, but it can be difficult and costly to get at the raw gaseous stuff, at least in the kind of commercial volumes that could sustainably fuel a hydrogen economy.  But researchers at the DOE's Lawrence Berkeley National Laboratory have made a substantial leap toward a hydrogen-based future by devising a cheap, metal catalyst that can split hydrogen gas from water.

The ability to pull apart H2O molecules into their constituent atoms is, of course, the key to creating a hydrogen-based energy economy.  If we can do so in a cheap and energy efficient manner, we could potentially turn Earth's vast supply of water into our own vast supply of cheap, clean power.

But most hydrogen gas on earth comes packaged as natural gas -- a carbon-based fuel -- or packed into water, which can be split into oxygen and hydrogen through a process called electrolysis.  Electrolysis requires a good deal of electricity, but if renewable fuels generate that power the process can be carbon neutral. What it can't be is cheap; electrolysis requires a catalyst to split water into oxygen and hydrogen gas, the most common of which is platinum, which retails at some $2,000 per ounce.

Seeking to drive the cost of electrolysis down to more reasonable levels, the Berkeley Lab team devised a high-valence metal they're calling Mo-oxo for molybdenum-oxo (PY5Me2, for you chem. geeks out there).  The catalyst requires no additional organic additives or solvents, can operate in neutral water (even if it's dirty) and works with sea water -- meaning we could literally be looking at oceans of cheap energy.  Best of all: Mo-oxo is about 70 times cheaper than platinum.

Don't expect to see Mo-oxo splitting seawater into large volumes of hydrogen gas right away. The research is still preliminary and the Berkeley team is just getting into some of the more exciting chemistry.  They're looking for additional similar metals that might generate hydrogen gas at even higher efficiency, so by the time this kind of tech is commercialized we may have found an even better catalyst.  In the meantime, Mo-oxo marks a sort of corner-turning for water electrolysis.  Any great shift to non-carbon fuels is ultimately going to be driven by economics, and finding less expensive ways to generate hydrogen gas is integral to kicking off that sea change.