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*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
  Prev <http://www.sciencemag.org/cgi/content/short/321/5889/619e> | Table
of Contents <http://www.sciencemag.org/content/vol321/issue5889/index.dtl> |
Next <http://www.sciencemag.org/cgi/content/short/321/5889/621>
  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<http://www.sciencemag.org/cgi/content/full/321/5889/671>and
676 <http://www.sciencemag.org/cgi/content/full/321/5889/676>, 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).

 [image: Figure 1]<http://www.sciencemag.org/cgi/content/full/321/5889/620/F1>
*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 Co
3+, 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.

 ------------------------------
 The editors suggest the following Related Resources on *Science* sites: In
*Science* Magazine *REPORTS*
High Rates of Oxygen Reduction over a Vapor Phase–Polymerized PEDOT
ElectrodeBjorn Winther-Jensen, Orawan Winther-Jensen, Maria Forsyth, and
Douglas R. MacFarlane (1 August 2008)
*Science* *321* (5889), 671. [DOI: 10.1126/science.1159267]
 |  Abstract »<http://www.sciencemag.org/cgi/content/abstract/sci;321/5889/671>
|  Full Text » <http://www.sciencemag.org/cgi/content/full/sci;321/5889/671>
|  PDF » <http://www.sciencemag.org/cgi/reprint/sci;321/5889/671.pdf>
|  Supporting
Online Material
»<http://www.sciencemag.org/cgi/content/full/sci;321/5889/671/DC1>
*REPORTS*
Colossal Ionic Conductivity at Interfaces of Epitaxial
ZrO2:Y2O3/SrTiO3HeterostructuresJ.
Garcia-Barriocanal, A. Rivera-Calzada, M. Varela, Z. Sefrioui, E. Iborra, C.
Leon, S. J. Pennycook, and J. Santamaria (1 August 2008)
*Science* *321* (5889), 676. [DOI: 10.1126/science.1156393]
 |  Abstract »<http://www.sciencemag.org/cgi/content/abstract/sci;321/5889/676>
|  Full Text » <http://www.sciencemag.org/cgi/content/full/sci;321/5889/676>
|  PDF » <http://www.sciencemag.org/cgi/reprint/sci;321/5889/676.pdf>
|  Supporting
Online Material
»<http://www.sciencemag.org/cgi/content/full/sci;321/5889/676/DC1>


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.
>



-- 
******************************************
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
******************************************