Energy from Water and Sunlight

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OPEN 2009
Cambridge, Massachusetts
Project Term:
12/31/2009 - 12/31/2012

Technology Description:

Sun Catalytix is developing wireless energy-storage devices that convert sunlight and water into renewable fuel. Learning from nature, one such device mimics the ability of a tree leaf to convert sunlight into storable energy. It is comprised of a silicon solar cell coated with catalytic materials, which help speed up the energy conversion process. When this cell is placed in a container of water and exposed to sunlight, it splits the water into bubbles of oxygen and hydrogen. The hydrogen and oxygen can later be recombined to create electricity, when the sun goes down for example. The Sun Catalytix device is novel in many ways: it consists primarily of low-cost, earth-abundant materials where other attempts have required more expensive materials like platinum. Its operating conditions also facilitate the use of less costly construction materials, whereas other efforts have required extremely corrosive conditions.

Potential Impact:

If successful, Sun Catalytix would generate stored solar energy that is cost competitive with the current price of gasoline or diesel fuel.


Increasing renewable energy storage could help increase the reliability of the electric grid.


Electricity generation accounts for over 40% of U.S. carbon dioxide (CO2) emissions. Enabling large-scale contributions of wind and solar power for our electricity generation would result in a substantial decrease in CO2 emissions.


Decreasing demand for fossil fuels would help reduce fuel prices and stabilize electricity rates.


ARPA-E Program Director:
Dr. Mark Johnson
Project Contact:
Dr. Thomas Jarvi
Press and General Inquiries Email:
Project Contact Email:

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