Chemistry Chair Leads Research on Solar Energy, Water, and Hydrogen in Creating a New Fuel Source

By Peter Grennen

It's proof that Occam's razor still compels. Recent efforts to find alternatives to fossil fuels seem to have been guided by the principle--named for the fourteenth-century philosopher William of Occam--that in science the familiar should be preferred to the unknown, the simple to the more complex. And a research team headed by Chemistry Department chairman Stuart Licht is continuing this trend back to basics, having demonstrated an energy-producing technique that makes thorough use of one of nature's most plentiful resources.

Certainly, the fuel now being touted as gasoline's successor is as simple and familiar a substance as there is. The state of the art in this area of research is an energy cell that burns hydrogen, the most basic and abundant element in the universe. Problem is, thus far attempts to mass-produce hydrogen fuel have been anything but productive: Most naturally occurring hydrogen is found in chemical compounds, and isolating a pure form of the gas is both difficult and costly. What's worse, the current method of choice requires steam and natural gas, a pollutant like any other fossil fuel.

Solar generators of hydrogen do away with natural gas in favor of two other commodities nature provides in abundance: water and sunlight. The electrical energy contained in light from the sun is used to split water molecules into separate hydrogen and oxygen molecules. "This is a fundamental step in hydrogen production," says Licht, "because it confirms that we can create tremendous amounts of hydrogen simply by using solar energy and water."

The method is safe for the environment--its only by-product is water--but it has not proved to be cost-effective, since it is only 18 percent efficient. This means that the amount of hydrogen generated by the process stores 82 percent less energy than does the light used to produce it.

Licht's technique markedly improves upon those numbers--and without materially altering the model. The process uses the thermal energy produced by the infrared portion of the sun's energy spectrum to heat water to 600 degrees Celsius. The water is then placed in an alkaline solution and subjected to electrical energy that splits it into hydrogen and oxygen molecules.

The technique's efficiency rating of 30 percent is attributable in large measure to its full-bore use of the sun's output. "The key difference is the use of the thermal portion of the photons," says Licht. "We're taking advantage of the entire spectrum and using different portions of it to achieve different ends."

It's a development that could help make hydrogen as easy to obtain as any other fuel source. Till then, however, this science must answer to the "dismal science" of economics. Hydrogen is still four times as expensive as gasoline, and fuel cells are ten times more expensive to build than a conventional automobile engine. Experts say that for hydrogen fuel cells to see widespread use in cars, these costs must be drastically reduced.
Not to suggest that the cells are about to join the Hindenburg on the scrap heap of hydrogen-fueled inventions. Research in this area, lately given greater urgency by world geopolitical events, continues to be a priority in industrialized nations. "Solar (power) is opening up a lot of very exciting possibilities," said Licht. "We're heading toward a society that uses clean hydrogen as its primary fuel."

It's been said there's nothing new under the sun--and Licht's work adds new meaning to that claim. As scientists continue to shine light on as-yet-unexplored areas of our physical environment, discoveries such as this one may well lead them to conclude that finding sustainable energy sources is simplicity itself.

Image: Stuart Licht, chair of the Chemistry Department, is leading a research team investigating ways to make hydrogen an easier-to-obtain fuel source.

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