How the plants do it

A team of MIT researchers has found a novel way to mimic the process by which plants use the power of sunlight to split water. In this case, the team used a modified virus to assemble the nanoscale components needed to split a water molecule into hydrogen and oxygen atoms. Splitting water is one way to solve the basic problem of solar energy: It's only available when the sun shines. By using sunlight to make hydrogen from water, the hydrogen can then be stored and used at any time to generate electricity using a fuel cell, or to make liquid fuels.

The new biologically based system skips the intermediate steps and uses sunlight to power the reaction directly.

The advance is described in a paper published on April 11 in Nature Nanotechnology.
The team engineered a common, harmless bacterial virus called M13 so that it would attract and bind with molecules of a catalyst (the team used iridium oxide) and a biological pigment (zinc porphyrins). The viruses became wire-like devices that could very efficiently split the oxygen from water molecules.

Other researchers have tried to use the photosynthetic parts of plants directly for harnessing sunlight, but these materials can have structural stability issues.