Researchers at the Massachusetts Institute of Technology (MIT) have discovered a method of splitting a water molecule by copying photosynthesis, the process plants use to convert water, carbon dioxide and sunlight to fuel that helps them grow.

The scientists have created a method of using sunlight to initiate a reaction that separates oxygen atoms from water molecules more efficiently than other methods.

They eventually hope to use a similar method to just as efficiently produce hydrogen gas, which can be stored and used to create electricity to power vehicle fuel cells, for example.

Using solar energy directly as a power source, such as in solar panels, requires constant exposure to sunlight. But using it to split water creates hydrogen gas, an energy source that can be used even when the sun isn't shining.

To separate the H20 molecule, the MIT researchers engineered a harmless virus, dubbed M13, that could act as a platform, or "biological scaffolding," on which the splitting reaction could take place.

The team used the same components as plants do to promote the reaction: a pigment to absorb sunlight and a catalyst to spur the splitting of the water molecule.

The pigment (in the researchers case, zinc porphyrins) acted "as an antenna to capture the light and then transfer the energy down the length of the virus like a wire," said Angela Belcher, the Germeshausen professor of Materials Science and Engineering and Biological Engineering, in a news release.

The virus simply acted as the staging ground that allowed the pigment and the catalyst to align in a way that would trigger the splitting reaction.

"We use components people have used before, but we use biology to organize them for us, so you get better efficiency," Belcher said.

Improved efficiency of oxygen production fourfold

Researchers chose to focus their efforts on the separation of oxygen from the water molecules as it is the more "technically challenging half-reaction" of that process, an MIT press release announcing the research said.

Using their virus method, they managed to raise the output of oxygen fourfold over what it would usually be.

They now hope to find a similar biologically based method to perform the second half of the reaction: the production of hydrogen gas. In their initial half-reaction, hydrogen atoms from the water end up split into electrons and protons — and scientists want to combine these into hydrogen atoms and molecules.

The scientists believe their findings are novel. While systems already exist to split water molecules and create hydrogen gas using electricity, which can be generated through solar panels, the MIT system powers the reaction directly through sunlight.

Though the research is in the early stages and a commercial product could be many years away, other scientists praised the research.

"To be cost-competitive with other approaches to solar power, the system would need to be at least 10 times more efficient than natural photosynthesis, be able to repeat the reaction a billion times and use less expensive materials," said Thomas Mallouk, the DuPont Professor of Materials Chemistry and Physics at Pennsylvania State University, who was not involved in this work.

"This is unlikely to happen in the near future. Nevertheless, the design idea illustrated in this paper could ultimately help with an important piece of the puzzle."

The findings were published on April 11 in Nature Nanotechnology. The lead author of the paper is doctoral student Yoon Sung Nam.