High-speed method to aid search for solar energy storage catalysts

May 25, 2012 by Terry Devitt

Eons ago, nature solved the problem of converting solar energy to fuels by inventing the process of photosynthesis.

Plants convert sunlight to in the form of biomass, while releasing oxygen as an environmentally benign byproduct. Devising a similar process by which could be captured and stored for use in vehicles or at night is a major focus of modern solar energy research.

"It is widely recognized that solar energy is the most abundant source of energy on the planet," explains University of Wisconsin-Madison chemistry professor Shannon Stahl. "Although solar panels can convert sunlight to electricity, the sun isn't always shining."

Thus, finding an efficient way to store solar energy is a major goal for science and society. Efforts today are focused on electrolysis reactions that use sunlight to convert water, carbon dioxide, or other abundant into chemicals that can be stored for use any time.

A key stumbling block, however, is finding inexpensive and readily available electrocatalysts that facilitate these solar-driven reactions. Now, that quest for catalysts may become much easier thanks to research led by Stahl and UW-Madison staff scientist James Gerken and their colleagues.

Writing this week in the journal , the Wisconsin group describes a new high-throughput method to identify electrocatalysts for .

Efficient, earth-abundant electrocatalysts that facilitate the oxidation of water are critical to the production of , says Gerken. "If we do this well enough, we can keep the party going all night long."

Existing technology to store solar energy is not economically viable because using the sun to split water into oxygen and hydrogen is inefficient. Water oxidation provides electrons and protons needed for , and better catalysts minimize the energy lost when converting energy from sunlight to chemical fuels, says Stahl.

In addition to being efficient, the catalysts need to be made from materials that are more abundant and far less expensive than metals like platinum and the rare earth compounds currently found in the most effective catalysts.

According to Stahl and Gerken, the discovery of promising electrocatalytic materials is hindered by the costly and laborious approaches used to discover them. What's more, the sheer number of possible catalyst compositions far exceeds the number that can be tested using traditional methods.

In the Angewandte Chemie report, Gerken, Stahl and their colleagues describe a screening method capable of rapidly evaluating potential new electrocatalysts. In simple terms, the technique works using ultraviolet light and a fluorescent paint to test prospective metal-oxide electrocatalysts. A camera captures images from a grid of candidate catalysts during the electrolysis process, as the paint responds to the formation of oxygen. This approach turns out to be a highly efficient way to sort through many compounds in parallel to identify promising leads.

Already, the Wisconsin team has identified several new metal-oxide catalysts that are composed of inexpensive materials such as iron, nickel and aluminum, and that hold promise for use in solar energy storage.

In addition to Gerken and Stahl, authors of the new study include Jamie Y.C. Chen, Robert C. Massé, and Adam B. Powell, all of UW-Madison's department of chemistry. The work was supported by a grant from the U.S. National Science Foundation and a provisional patent has been submitted through the Wisconsin Alumni Research Foundation.

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User comments : 4

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Going
5 / 5 (1) May 25, 2012
Whoever finds an economic way to capture and store renewable energy will make millions.
hikenboot
not rated yet May 26, 2012
Goinq probably billions is more like it...
Cave_Man
not rated yet May 26, 2012
im pretty sure the new carbon nanotube super-insulating capacitors should do the trick.

what would be even better though is worldwide infrastructure to share energy on a credit based system where energy is transferred around the globe to whoever needs it with less loss than storage and retrieval.

Personally I hate solar panels, they use toxic elements and only produce like 120% of the energy required to manufacture them in their entire rated lifetime. Solar thermal on the other hand is cheaper, easier to maintain and lasts A LOT longer than PV panels.

Why has nobody designed a solar thermal space station yet? From what I hear the exhaust heat is a big problem in space since there is negligible conduction to remove heat from components. So why not harvest that heat and heat from the sun to run simple turbines that would also suffer less from friction loss since there is little gravity to contend with.
Bowler_4007
1 / 5 (1) May 26, 2012
"the sun isn't always shining".
And money grows on trees. They should have said something along the lines of "Sunlight isn't always accessible".

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