Drawing inspiration from Mother Nature in designing an ‘artifical leaf’


March 26, 2010

Scientists have taken a leaf from Mother Nature's book in designing a blueprint for an artificial leaf

Scientists have taken a leaf from Mother Nature's book in designing a blueprint for an artificial leaf

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Producing an artificial leaf capable of harnessing Mother Nature’s ability to produce energy from sunlight and water via photosynthesis has been a long-sought goal for researchers aspiring to provide an environmentally-friendly way to free to world of its dependence on coal, oil, and other carbon-producing fuel sources. Now a group of Chinese scientists has presented a design strategy based on the chemistry and biology of natural leaves that could lead to working prototypes of an artificial leaf that captures solar energy and uses it efficiently to change water into hydrogen fuel.

The structure of green leaves provides them with an extremely high light-harvesting efficiency. Within their architecture are structures responsible for focusing and guiding solar energy into the light-harvesting sections of the leaf, and other functions.

For this reason the scientists from State Key Lab of Matrix Composites at Shanghai Jiaotong University, Shanghai, China, decided to mimic that natural design in the development of a blueprint for artificial leaf-like structures. It led them to their recipe for the "Artificial Inorganic Leaf" (AIL), based on the natural leaf and titanium dioxide (TiO2) - a chemical already recognized as a photocatalyst for hydrogen production.

The scientists first infiltrated the leaves of Anemone vitifolia - a plant native to China - with titanium dioxide in a two-step process. Using advanced spectroscopic techniques, the scientists were then able to confirm that the structural features in the leaf favorable for light harvesting were replicated in the new TiO2 structure. They found the AIL to be eight times more active for hydrogen production than TiO2 that had not been "biotemplated" in that fashion. AILs also are more than three times as active as commercial photo-catalysts.

Next, the scientists embedded nanoparticles of platinum into the leaf surface. Platinum, along with the nitrogen found naturally in the leaf, helps increase the activity of the artificial leaves by an additional factor of ten.

"This concept may provide a new vista for the design of artificial photosynthetic systems based on biological paradigms and build a working prototype to exploit sustainable energy resources," doctors Tongxiang Fan, Di Zhang and Han Zhou reported.

Using sunlight to split water into its components, hydrogen and oxygen, is one of the most promising and sustainable tactics to escape current dependence on coal, oil, and other traditional fuels. That appeal is central to the much-discussed "Hydrogen Economy," and some auto companies, such as Honda, have already developed hydrogen-fueled cars. Lacking, however, is a cost-effective sustainable way to produce hydrogen. Drawing on Mother Nature could well provide the answer.

The team from the State Key Lab of Matrix Composites at Shanghai Jiaotong University will present its design strategy report at the 239th National Meeting of the American Chemical Society being held this week.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Same comment for this new energy idea! Besides looking for independent confirmation of claims, I\'ve lost count of the different ideas and techniques on new energy production that have hit the press over the last few years. It would be nice to see how many of these type ideas have come to fruition and are in full-swing, efficient production. I\'m not as interested in the big picture comparison of how much energy they make as compared to ALL other forms of energy used. At this early point, it would be but a drop in the old bucket! What I would like to see is actual production volume as compared to the total energy used in the production process. It should include any energy produced that was then cycled back into the production side.There has got to be a name for this ratio idea but it escapes me. For instance, the ratio for producing hydrogen in quantity was for years way too far in the negative, taking more energy to make it than was produced!

Will, the tink

To take your comment further William I would be interested in knowing if this technology would be feasible to work in conjunction with desalination plants or whether or not clean water is even needed for the process (i.e. could salt water be used?).

Is the technology capable of running a desalination plant and then using that clean water to produce oxygen and hydrogen? Can the hydrogen produced be used to perperuate the cycle? What happens when some of the energy is taken out of the system?

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