Science

Inexpensive metal catalyst discovered for electrolytic production of hydrogen from water

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The hydrogen economy that may one day replace the hydrocarbon economy came a step closer this week with the announcement that researchers have discovered an inexpensive new proton reduction catalyst - seventy times cheaper than the platinum commonly used now - that can significantly reduce the costs of producing hydrogen using electrolysis to split water into molecules of hydrogen and oxygen.

The important step was discovered 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. "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, one of the co-discoverers of this complex. "These qualities make our catalyst ideal for renewable energy and sustainable chemistry."

Karunadasa holds joint appointments with Berkeley Lab's Chemical Sciences Division and UC 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.

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.

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 US$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."

19 comments
Nick Gencarelle
Sweet-hope it does not take years and years to get to the table-and or bought out and snuffed by large energy corporations and governments-we need this stuff NOW-where is the fast track?
Dan Linder
Like many other breakthroughs, how many decades will it be until this catalyst is actually in use outside the laboratory?
jerryd
This won\'t make any difference in H2 use as H2 has more serious problems beside electrodes. My EV goes 4-8x\'s as far on the same energy as a H2 car does at a much lower costs for the equipment.
kwalker
Gee, we will soon be able to use mass quantities of water for fuel. Um... what about all that talk about water being a scarce resource and that there will be shortages in the not too distant future? Maybe we should find a way to make fuel out of waste products, or from fingernail clippings or something.
Anthony Parkerwood
@kwalker they mention using sea water.
t2af
@kwalker i\'m pretty sure people are talking about fresh water when they talk about scarce resources. As the article states; this new catalyst can be used with sea water, roughly 2/3rds of the earths surface.
phill
@kwalker: Um... there is no scarcity of sea water, which this system is supposed to work with.
Dr.A.Jagadeesh
Inexpensive new proton reduction catalyst - seventy times cheaper than the platinum commonly used now - that can significantly reduce the costs of producing hydrogen using electrolysis to split water into molecules of hydrogen and oxygen by researchers with the U.S. Department of Energy\'s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley.will be a new approach to speed up HYDROGEN ENERGY AS CARRIER. Dr.A.Jagadeesh Nellore(AP),India.
windykites
Let\'s not forget that you can electrolyse H2 from water without using exotic catalysts. The electricity could come from solar cells
bk425
\"Gee, we will soon be able to use mass quantities of water for fuel\" Electrolytic Hydrogen like this doesn\'t \"use\" water, it emits water from chemically \"burning\" the catalyst. So it\'s more like electrolysis is storing power in the catalyst and releasing it as heat(or electricity) and water. Maybe some water gets bound up in that cycle but it\'s a -cycle- of store and release. The question here should be what\'s driving the electrolysis. Much like the folks who are excited about their plug in cars, people forget that it\'s coal/petroleum/nuclear that makes the magic come out of that plug in their garage. Not actually... magic. -Boyd (who never even took a chem class)
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