Viable water into hydrogen fuel concept

It has long been known that plants, bacteria and algae are capable of turning sunlight into fuel. Now researchers at Penn State University have what is known as a ‘proof-of-concept device’ that is capable of splitting water to produce hydrogen, which can be used as fuel.

Professor of Materials Chemistry and Physics, Thomas E. Mallouk said in a statement, “This is a proof-of-concept system that is very inefficient. But ultimately, catalytic systems with 10 to 15 percent solar conversion efficiency might be achievable,” And “If this could be realized, water photolysis would provide a clean source of hydrogen fuel from water and sunlight.”

We have already developed solar cells that are capable of producing electricity from sunlight. Hydrogen cells also produced by scientists at Penn State have been successful with limited response, in the semiconductors used for testing.

In theory, molecular light absorbers would be able to use more of the visible spectrum through a process that mimics photosynthesis in plants. Until now, experiments using natural and synthetic dyes have produced hydrogen chemicals that are consumed during the process. However, they have been unable to create a viable continuous process.

All work done so far would not be cost-effective in that splitting the water uses more electricity than the fuel it produced. Mallouk has developed a catalyst, which when combined with a special dye mimics the electron transfer and water oxidation that occurs in natural photosynthesis.

“Each surface iridium atom can cycle through the water oxidation reaction about 50 times per second,” says Mallouk. “That is about three orders of magnitude faster than the next best synthetic catalysts, and comparable to the turnover rate of Photosystem II in green plant photosynthesis.” Photosystem II is the protein complex in plants that oxidizes water and starts the photosynthetic process.

The scientists impregnate a titanium dioxide electrode with a catalyst complex, and then drop these electrodes into a simple salt solution. Then by exposing them to light, the light is then converted into hydrogen.

The splitting of water molecules only requires one volt of electricity, making it viable for hydrogen fuel production.

“Nature is only 1 to 3 percent efficient with photosynthesis,” says Mallouk. “Which is why you can not expect the clippings from your lawn to power your house and your car. We would like not to have to use all the land area that is used for agriculture to get the energy we need from solar cells.”
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