Artificial Photosynthesis

Man, since long, has tried to implement the methods of nature but nothing that the man does has the same perfection as that of nature.

No factory can generate water pure as the coconut trees or water melons.

Studies have shown that the brain of a person has greater storage and processing capacity when compared to a computer. The olfactory receptors of the dog are more sensitive than any sensor science has ever been able to develop. The early warning systems seem primitive when compared to the sixth sense animals possess. And yes, no one has reached an energy production system as efficient as the photosynthesis.

Yes the new phrase is Artificial Photosynthesis.

We are all aware of the energy crisis we live in and of the innumerable alternative sources of energy that are being thought of, implemented and yet, do not satisfy the needs of a thriving world. It is definitely the necessity of the hour to explore alternative sources of energy as the countries of the world prosper and the fuels diminish. It is true that we are now aiming towards utilization of various other alternative methods. But if we look at it on long–term basis, we find that solar power cannot produce industrial quantities of electricity; the tide is turning against wind turbines because they spoil the landscape and too many would be needed to replace conventional generators; Nuclear energy remains in the doldrums and fossil fuels continue to threaten global warming.

Hydrogen is regarded as the energy carrier of the future. The automobile industry, for example, is working hard to introduce fuel cell technology starting in approximately the year 2010. However, a fuel cell drive system can be really environmentally friendly only if researchers succeed in producing hydrogen from renewable sources.

In such a situation, a new contender in the field is the harnessing of photosynthesis! The idea is to create an artificial system that exploits the basic chemistry of photosynthesis in order to produce hydrogen or other fuels both for engines and electricity. Hydrogen burns cleanly, yielding just water and energy. There is also the additional benefit that artificial photosynthesis could mop up any excess carbon dioxide left over from our present era of profligate fossil fuel consumption. Thus, it prevents global warming as well.

The artificial photosynthesis systems will mimic the water-splitting chemistry of natural photosynthesis. Artificial systems will use metals such as ruthenium and iron to capture light and provide a scaffold for the water-splitting core. But the core itself would be based on manganese.

One of the major challenges to be overcome is the formation of aggressive substances in the process of water oxidation which can be easily overcome by a plant by replacing its green catalysts but not so easily artificially. Good news is that on March 27, 2008, a team from Research Centre Jülich, member of the Helmholtz Association, and from Emory University in Atlanta, USA has created a new inorganic metal oxide cluster with a core consisting of four ions of the rare transition metal ruthenium catalyses the fast and effective oxidation of water to oxygen while remaining stable itself. Now the challenge is to integrate this ruthenium complex into photoactive systems, which efficiently convert solar energy into chemical energy.

So hopefully, in the near future, man will be able to generate energy successfully through artificial photosynthesis. But the question remains, can man achieve the efficiency of nature?

Ayushi Uberoi


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