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March 12, 2009, 5:52 pm

Turning sunlight into liquid fuel

Plants find it easy to trap sunlight into organic molecules which can be used as fuel - so why can't we? Photosynthesis is not so easy to copy, but now we are one step closer...

Paul Alivisatos was a speaker at the Molecular Frontiers symposium "Alternative Energy & Molecules" at the Royal Academy of Sciences in Stockholm in June 2010.

Watch an interview with him, choose questions to ask, here!


What was discovered?

It sounds unbeleivable that we should struggle so hard to do what plants do best! 

Photosynthesis is a remarkable process, whereby light energy is used by chlorophyll inside the membranes of the chloroplast to split water in the start of the reactions needed to make glucose .

The carbon for making the glucose comes from carbon dioxide in the air or water around the plant.

Glucose is the food of the plant - it can be used as a building block for many other molecules, such as cellulose for cell walls.

Imagine sunning yourself and getting fed and building your body at the same time using nothing more than water and the air around you!

Scientists have now found that nano-sized crystals of cobalt oxide can be used to split water molecules into oxygen , electrons and protons (hydrogen ions): this is called photo-oxidation. In plants this is done by proteins in a structure called Photosystem II.

Luckily cobalt oxide is both cheap and abundant... so it looks like the first major step of copying photosynthesis has been achieved using materials that could be used to mass produce organic molecules for fuel.

BTW - we shouldn't get too smug... bacteria have been able to photosynthesize for millions of years too, using different molecules... do you know which ones?


Lesson plans: Photosynthesis, trees and the Greenhouse effect




See also

Paul Alivisatos
Nanoparticles can be used to make materials with new properties, which could be the key to solving problems like how to best capture the energy from the sun. Meet one of the world's...
Forum question
How can the process of photosynthesis be used as a source of renewable energy? Can the light driven electron flow mediated by proteins generate our electricity?