The press release is very hyped up, but I see that our own news story (see below) is pretty positive as well. Robert Service is an excellent journalist and it is our practice to search out critical comment if it exists. Perhaps this is potential good news.


Science 1 August 2008:
Vol. 321. no. 5889, p. 620
DOI: 10.1126/science.321.5889.620

News of the Week

CHEMISTRY:
New Catalyst Marks Major Step in the March Toward Hydrogen Fuel

Robert F. Service

Climate change concerns, high gas prices, and a good deal of international friction would fade if scientists could learn a trick every houseplant knows: how to absorb sunlight and store its energy in chemical bonds. What's needed are catalysts capable of taking electricity and using it to split water to generate hydrogen gas, a clean fuel. Unfortunately, the catalysts discovered so far work under harsh chemical conditions, and the best ones are made from platinum, a rare and expensive metal.

No more. This week, researchers at the Massachusetts Institute of Technology (MIT) in Cambridge led by chemist Daniel Nocera report online in Science a new water-splitting catalyst that works under environmentally friendly conditions (www.sciencemag.org/cgi/content/abstract/1162018). More important, it's made from cobalt and phosphorus, fairly cheap and abundant elements. The new catalyst needs improvements before it can solve the world's energy problems, but several outside researchers say it's a crucial development.

"This is a great result," says John Turner, an electrochemist and water-splitting expert at the National Renewable Energy Laboratory in Golden, Colorado. Thomas Moore, a chemist at Arizona State University in Tempe, goes further. "It's a big-to-giant step" in the direction of powering industrial societies with renewable fuels, he says. "I'd say it's a breakthrough." Meanwhile, on pages 671 and 676, other groups report related advances--a cheap plastic fuel cell catalyst that converts hydrogen to electricity, and a solid oxide fuel cell catalyst that operates at lower temperatures--that affect another vital component of any future solar hydrogen system.

English chemists first used electricity to split water more than 200 years ago. The reaction requires two separate catalytic steps. The first, the positively charged electrode, or anode, swipes electrons from hydrogen atoms in water molecules. The result is that protons (hydrogen atoms minus their electrons) break away from their oxygen atoms. The anode catalyst then grabs two oxygen atoms and welds them together to make O2. Meanwhile, the free protons drift through the solution to the negatively charged electrode, or cathode, where they hook up with electrons to make molecular hydrogen (H2).

Figure 1 Water power. Cobalt-phosphorus catalyst opens the way to using sunlight to extract hydrogen from water.

CREDIT: JOSEPH SOHM/VISIONS OF AMERICA/CORBIS

The hard part is finding catalysts that can orchestrate this dance of electrons and protons. The anode, which links oxygens together, has been a particularly difficult challenge. Platinum works but is too expensive and rare to be viable on an industrial scale. "If we are going to use solar energy in a direct conversion process, we need to cover large areas," Turner says. "That makes a low-cost catalyst a must." Other metals and metal oxides can do the job but not at a neutral pH--another key to keeping costs down. In 2004, Nocera's team reported in the Journal of the American Chemical Society a cobalt-based catalyst that did the reverse reaction, catalyzing the production of water from O2, protons, and electrons. "That told us cobalt could manage multielectron and proton-coupled reactions," Nocera says.

Unfortunately, cobalt is useless as a standalone water-splitting anode because it dissolves in water. Nocera and his Ph.D. student Matthew Kanan knew they couldn't get over this hurdle. So they went around it instead. For their anode, they started with a stable electrode material known as indium tin oxide (ITO). They then placed their anode in a beaker of water, which they spiked with cobalt (Co2+) and potassium phosphate. When they flipped on the current, this created a positive charge in the ITO. Kanan and Nocera believe this initially pulls electrons from the Co2+, turning it first to Co3+, which pairs up with negatively charged phosphate ions and precipitates out of solution, forming a film of rocklike cobalt phosphate atop the ITO. Another electron is yanked from the Co3+ in the film to make Co4+, although the mechanism has not yet been nailed down. The film forms the critical water-splitting catalyst. As it does so, it swipes electrons from hydrogen atoms in water and then grabs hold of lone oxygen atoms and welds them together. In the process, the Co4+ returns to Co2+ and again dissolves into the water, and the cycle is repeated.

The catalyst isn't perfect. It still requires excess electricity to start the water-splitting reaction, energy that isn't recovered and stored in the fuel. And for now, the catalyst can accept only low levels of electrical current. Nocera says he's hopeful that both problems can be solved, and because the catalysts are so easy to make, he expects progress will be swift. Further work is also needed to reduce the cost of cathodes and to link the electrodes to solar cells to provide clean electricity. A final big push will be to see if the catalyst or others like it can operate in seawater. If so, future societies could use sunlight to generate hydrogen from seawater and then pipe it to large banks of fuel cells on shore that could convert it into electricity and fresh water, thereby using the sun and oceans to fill two of the world's greatest needs.




On Sat, Aug 2, 2008 at 6:19 AM, Phil Gasper <[log in to unmask]> wrote:
http://web.mit.edu/newsoffice/2008/oxygen-0731.html
'Major discovery' from MIT primed to unleash solar revolution
Scientists mimic essence of plants' energy storage system

Anne Trafton, News Office
July 31, 2008
In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Until now, solar power has been a daytime-only energy source, because storing extra solar energy for later use is prohibitively expensive and grossly inefficient. With today's announcement, MIT researchers have hit upon a simple, inexpensive, highly efficient process for storing solar energy.

Requiring nothing but abundant, non-toxic natural materials, this discovery could unlock the most potent, carbon-free energy source of all: the sun. "This is the nirvana of what we've been talking about for years," said MIT's Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT and senior author of a paper describing the work in the July 31 issue of Science. "Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon."

Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera's lab, have developed an unprecedented process that will allow the sun's energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night.

The key component in Nocera and Kanan's new process is a new catalyst that produces oxygen gas from water; another catalyst produces valuable hydrogen gas. The new catalyst consists of cobalt metal, phosphate and an electrode, placed in water. When electricity -- whether from a photovoltaic cell, a wind turbine or any other source -- runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.

Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in neutral pH water, and it's easy to set up, Nocera said. "That's why I know this is going to work. It's so easy to implement," he said.
'Giant leap' for clean energy

Sunlight has the greatest potential of any power source to solve the world's energy problems, said Nocera. In one hour, enough sunlight strikes the Earth to provide the entire planet's energy needs for one year.

James Barber, a leader in the study of photosynthesis who was not involved in this research, called the discovery by Nocera and Kanan a "giant leap" toward generating clean, carbon-free energy on a massive scale.

"This is a major discovery with enormous implications for the future prosperity of humankind," said Barber, the Ernst Chain Professor of Biochemistry at Imperial College London. "The importance of their discovery cannot be overstated since it opens up the door for developing new technologies for energy production thus reducing our dependence for fossil fuels and addressing the global climate change problem."

'Just the beginning'

Currently available electrolyzers, which split water with electricity and are often used industrially, are not suited for artificial photosynthesis because they are very expensive and require a highly basic (non-benign) environment that has little to do with the conditions under which photosynthesis operates.
 
More engineering work needs to be done to integrate the new scientific discovery into existing photovoltaic systems, but Nocera said he is confident that such systems will become a reality.
 
"This is just the beginning," said Nocera, principal investigator for the Solar Revolution Project funded by the Chesonis Family Foundation and co-Director of the Eni-MIT Solar Frontiers Center. "The scientific community is really going to run with this."

Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past.

The project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet the needs of the future and to help build a bridge to that future by improving today's energy systems. MITEI Director Ernest Moniz, Cecil and Ida Green Professor of Physics and Engineering Systems, noted that "this discovery in the Nocera lab demonstrates that moving up the transformation of our energy supply system to one based on renewables will depend heavily on frontier basic science."
 
The success of the Nocera lab shows the impact of a mixture of funding sources - governments, philanthropy, and industry. This project was funded by the National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make the large scale deployment of solar energy within 10 years.



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Michael Balter
Contributing Correspondent, Science
Adjunct Professor of Journalism,
Boston University

Email: [log in to unmask]

Website: michaelbalter.com
Balter's Blog: michael-balter.blogspot.com
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