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Friday, June 14, 2013

Artificial Leaf - A reliable source of energy





We all know that leaves are the parts of the tree that gives the required energy for the growth by using the process of Photosynthesis. In the process of photosynthesis, leaves take in the sunlight, water and carbon dioxide and produces glucose and releases all important oxygen into the atmosphere. This is how the leaves harness solar energy and convert them into the energy required for its growth. In 2011 researchers at MIT developed an artificial leaf technology to convert the solar energy into the useful form that can power our present day generators. These are a boon in the areas which lack electrical transmission infrastructure where these can be used to generate the power with the help of abundant sunlight and water.

What exactly is an artificial leaf ??
        An artificial leaf is essentially a silicon solar cell that has different catalytic materials bonded to each other that allow it to split water molecules into oxygen and hydrogen. Among the split constituents hydrogen can be stored and can be used as  a clean fuel. The artificial leaf when placed in a jar containing water and exposed to sunlight it splits the water molecules into oxygen and hydrogen, These gases can be collected as they bubble up through the water. It is treated as one of the inexpensive mode of generating energy in remote areas as well as urban areas also. Though there are many devices that are being developed with this concept
artificial leaf stands out to be the affordable and easy option and it will become further more cheaper when once it is mass produced. With less than a liter(0.25 gal) of water we can produce nearly 100 watts of electricity 24 hours a day. Yes of course it is not an efficient energy generation process in terms of above figures. The main idea of the developers team is to sell more and more cheaper units so that the ultimate job will be done. So instead of using a more costly device like a high efficient solar panel, its better to use these cheap devices in a big number which sums up to a decent amount of electricity. The other drawback of these artificial leaves is that there is no direct conversion of sunlight into electricity just like in case of a solar panel instead it converts water into hydrogen under the presence of sunlight , which is stored and can further be used as fuel.
Recent Advancements:-
         If you operate these kind of artificial leaves in water after some time it is obvious that some sort of bacteria will develop on the surface which mitigates the energy generation process. So this creates a situation where pure water must be readily available for these unit's operation and pure water is a limited and costly resource. So to address this problem the same team under the spearhead of Daniel G. Nocera, Ph.D., worked on this bottleneck and added an amazing advancement for the already existing artificial leaf. The team introduced a self healing capacity for the artificial leaf meaning that the artificial leaf itself heals the formed layers of bacteria and continues the generation process without human involvement or cleaning. This facilitates to operate the artificial leaf with impure water also which is a cheap and general resource on the planet than pure water, making it feasible at any place in the world.
                      “Self-healing enables the artificial leaf to run on the impure, bacteria-contaminated water found in nature, We figured out a way to tweak the conditions so that part of the catalyst falls apart, denying bacteria the smooth surface needed to form a biofilm. Then the catalyst can heal and re-assemble.”Nocera said. 
Future scope:-
         It is clear that using these leaves hydrogen is split from water and the formed hydrogen is then stored which needs an additional equipment. Researchers are thinking in a direction where these artificial leaves are operated side by side with the technology which converts the Hydrogen into useful fuel for our generators. By integrating the conversion equipment with the artificial leaf it will become more adoptable and easy to use energy generation source.
 Since contaminated water and sunlight are the abundant resources in the universe, the techniques utilizing these resources will always be affordable and the beauty of these technique is that the energy generation in this case is purely personalized and this personalization is necessary to fight the prevailing energy crisis.

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