ARTIFICIAL PHOTOSYNTHESIS

When I look at a leaf, I wonder about its anatomy and its structure that enables it to trap CO2, one of the culprits of global warming, and liberate oxygen as its byproduct.

Plants, some bacteria and protistans are capable to use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the "fuel" used by all living things.
6H2O + 6CO2 ----------> C6H12O6+ 6O2

Our scientists have been busy trying to reproduce the process of photosynthesis.

Artificial photosynthesis has the potential to not only produce hydrogen that could be used as a clean fuel for vehicles but also mop up carbon dioxide from the atmosphere.

But the main hindrance was that such reaction required more energy and could proceed only when several energized electrons were available to contribute.

So far, nobody succeeded in making artificial multiple electron systems that could provide the necessary energy for artificial photosynthesis.
A system - that would comprise of a donor molecule that can absorb visible light and release many electrons, and a receiver molecule capable of accepting and storing those electrons.

Existing systems can donate and receive only one electron at a time. Visible photons can only contribute a limited amount of energy towards a chemical reaction which is absorbed by electrons involved in the reaction.

But recently, a team of Chinese researchers has found that carbon nano tubes mimic this important step in photosynthesis.

A team led by Xian-Fu Zhang at the Hebei Normal University of Science and Technology in Qinhuangdao, China, has found that single-walled carbon nanotubes could act as the chemical heart of a multiple electron system.

A carbon nanotube can accept one electron for every 32 carbon atoms it contains; hence could act as the receiver molecule in artificial photosynthesis.

Zhang's team realized that by covalently bonding a large number of PC molecules to a carbon nanotube, they could create a multiple electron system activated by visible light.

Such nanosystem could form a key component of an artificial photosynthesis model and once achieved, this would revolutionize the quality of life on our planet.

Journal Reference: ChemPhysChem (DOI: 10.1002/cphc.200800191)

Gayatri

"There is only one sin: That is weakness...The only saint is that soul that never weakens, faces everything, and determines to die game."