New Design Strategy for the Artificial Leaf
Scientists are quite optimistic that hydrogen will emerge as the fuel of the future and the world would be driven by ‘hydrogen economy’. The only byproduct of hydrogen fuel is water vapor. By using hydrogen fuel we can reduce the harmful effects of greenhouse gases. Currently many research labs are engaged in duplicating the phenomenon of photosynthesis to produce hydrogen fuel. What fascinates the scientists is the splitting of water into hydrogen and oxygen by using solar energy. A vast majority of scientists all over the world believe that we can get rid of our dependence on fossil fuels by breaking water into its components. Even some automobile companies such as Toyota are promoting hydrogen fueled cars. But till now the use of hydrogen as fuel is not cost effective. That is why we are still waiting for the ‘hydrogen economy’ to arrive.
Scientists are trying to develop a design that would be an artificial leaf but its function would be almost similar to natural leaf. Like a real leaf, the lab designed leaf too utilizes solar energy and water to produce hydrogen. In biology this process performed by green leaves is known as photosynthesis. Their methodology would take inspiration from chemistry and biology of natural leaves.
The above mentioned project is being carried out at State Key Lab of Matrix Composites at Shanghai Jiaotong University, Shanghai, China. Tongxiang Fan, Ph.D. states, “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.” His other team members are Di Zhang, Ph.D. and Han Zhou, also a Ph.D. They are preparing to attend the 239th National Meeting of the American Chemical Society (ACS) in San Francisco. It is one of the prestigious and largest scientific meet of 2010. In this meeting more than 12,000 scientific reports will be presented.
Fan and his co-workers decided to duplicate the natural design and development of a blueprint for artificial leaf like structures. They christened their creation as the “Artificial Inorganic Leaf” (AIL). They also used titanium dioxide (TiO2), as a photocatalyst for hydrogen production.
Researchers used the native plant of China, known as Anemone vitifolia for their experiments. They infiltrated the leaves of Anemone vitifolia with titanium dioxide in a two step process. They depended on advanced spectroscopic techniques to confirm the exact structural features in the leaf. These structural features helps in trapping the light energy of the sun. They replicated the same features in new TiO2 structure. It is found that the AIL are eight times more active for hydrogen production than TiO2. But it is true only when AIL has not been “biotemplated” in that fashion. Another plus point in favor of AILs is their activity is three times more in comparison with commercial photo-catalysts. The researchers also inserted the nanoparticles of platinum. It is a known fact that platinum along with the nitrogen increases the artificial leaves by an additional factor of ten.
Fan also articulated the fact that why his team’s artificial Inorganic Leaf production and its spectroscopic work are better than the existing ones. According to Fan the activity of AILs are significantly higher than those prepared with classic routes. Fan credits the better outcomes due to the hierarchical structures derived from natural leaves:
“Our results may represent an important first step towards the design of novel artificial solar energy transduction systems based on natural paradigms, particularly based on exploring and mimicking the structural design. Nature still has much to teach us, and human ingenuity can modify the principles of natural systems for enhanced utility.”