Sunday, July 13, 2008

Climate crisis breakthrough? Artificial photosynthesis "a step nearer"

The quest for a way to artificially recreate photosynthesis may be a step closer, thanks to a breakthrough by a team of Chinese researchers, who are investigating the use of carbon 'nanotubes'.

The key step, which is carried out continuously in plants, is the breakdown, using light, of water into its Hydrogen and Oxygen components: This has long been a goal of chemists, but has so far eluded them.

In layman's terms, the problem is energy: Visible light "can only contribute a limited amount of energy towards a chemical reaction. This energy is absorbed by electrons involved in the reaction." Photosnthesis requires that several electrons involved in the reaction are energised, and is referred to as a "multiple electron system".

The challenge has been to recreate these multiple electron systems in the lab, but so far no one has succeeded in creating one with sufficient energy to power photosynthesis.

The promise of Carbon nanotubes, is that their structure is such that for each 32 carbon atoms in its fabric, it can 'accept' (i.e. absorb) a single electron: this means that even a tiny nanotube could potentially absorb millions of electrons at a time, and could potentially act as a 'receiver molecule' for artificial photosynthesis.

Artificial photosynthesis promises an efficient way of producing Hydrogen, which could potentially provide a clean fuel for vehicles: all that would be needed is water. Although a long way off, this breakthrough satisfies a vital requirement of any future models.

Original here

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