An artificial leaf can heal itself
Researchers have been striving to create a power source that can be used in remote areas that lack sources of energy, and the 'leaf' is a step in that direction.
Thu, Apr 11, 2013 at 02:42 PM
Daniel Nocera’s artificial 'leaf' uses water and sunlight to create energy. (Photo: ACS)
A new artificial leaf that can produce energy using only water and sunlight is now able to now heal itself.
The man-made leaf, created by scientists at MIT led by Daniel Nocera, mimics the ability of natural plants to produce energy through photosynthesis. Their “leaf” is made of low-cost silicon and coated with hydrogen-oxygen catalysts designed to initiate chemical reactions. When introduced to water, the leaf’s catalysts break down the water into hydrogen and oxygen. The gas that rises out of the water can then be used in fuel cells to produce energy.
And the leaf is constantly improving. Nocera announced this week at the 245th National Meeting and Exposition of the American Chemical Society in New Orleans that the leaf is now capable producing energy from dirty water. Previous iterations of the leaf required pure water since bacteria in dirty water formed a film on the leaf that disabled energy production.
But a new, nonsmooth surface stops the formation of that film and now users don’t need to track down pure water, a development that is particularly exciting since the group believes the leaf has great potential for developing countries where pure water may be hard to come by.
An integral part of the leaf’s ability to use bacteria-contaminated water is its newly developed ability to self-heal, which was also presented at the meeting. When exposed to water bacteria, the catalyst coating on the leaf breaks down to create a rough surface that prevents the formation of the film. Later, the catalyst is able to reassemble and continue to break down water into hydrogen and oxygen.
“This is a nice property as it could mean that a robust compound could be built — ideally one that survives well in rough or remote conditions,” Dan Kammen, co-director of the Berkeley Institute of the Environment, told TechNewsDaily.
Nocera and his team have been striving to create a power source that can be used in remote areas that lack traditional sources of energy. The new artificial leaf has brought them one step closer to reaching that goal.
But some researchers in the field have their doubts. “I work in rural Africa, and the benefits of this design may be useful, but it is far from clear,” said Kammen, who was not involved in the project. “While this is an elegant design in the lab, dramatic cost declines in solar cells due to innovations and massive production efforts in China have already changed the game dramatically with huge price declines in solar. As a result, solar is already spreading rapidly across rural Africa.”
But the artificial leaf could be useful in other ways. Kammen believes that, if converted to an affordable spray or laminate, Nocera’s work could have far-reaching implications for use in urban environments where roof surfaces could house photovoltaics and contribute a significant amount of renewable energy to the grid. “In the U.S., one-third of our electricity needs [could be provided through roof areas],” said Kammen. “If these cells were cheap enough and flexible enough for urban surfaces, then they could be a player in an already rapidly expanding solar industry. The industry needs new innovative players. This could be one.”
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