Alternative fuel sources for cars may have a glowing future as a Kansas State
University graduate
student is working to replace petroleum fuels with ones made from sunlight.
Yen-Ting Kuo, a doctoral candidate in chemistry, Taiwan,
has spent several years in K-State’s chemistry program working to create new
materials that better use sunlight in chemical reaction processes to generate
energy.
“People tend to think of chemistry as test-tube experiments and not
really creating practical things. That’s just not true,” Kuo says. “A
big focus now is on ‘green chemistry.’ This means wanting to have the same
quality of life that we have right now, but using chemistry to replace some
things with materials that are more eco-friendly, such as biodegradable
products or clean fuel.”
As a way to advance the clean fuel research, Kuo is making and studying
metal-oxide catalysts that react with light. These catalysts, called
photocatalysts, cause a chemical reaction when triggered by sunlight, but are
not destroyed during the reaction. Photocatalysts are crucial to producing new
fuels, like solar gasoline, which use hydrogen.
To make solar gasoline, sunlight is channeled into a tank of water that
contains photocatalysts. The sunlight triggers the photocatalysts to react with
the water. This reaction causes the water to split into hydrogen and oxygen.
When the hydrogen is combined with carbon monoxide it forms a synthetic gas—called
syngas—that is the basic building block in fossil fuel and can be used to power
cars.
In recent years solar gasoline has been getting more mileage as more
international laboratories attempt to improve and perfect the process. But
developing a photocatalyst that efficiently uses sunlight to create a chemical
reaction and produce hydrogen is proving difficult for researchers. It also is
needed for production to reach commercial levels. Kuo is working to solve that
problem by creating and analyzing new photocatalysts in the lab.
To make a photocatalyst, Kuo mixes various elements in powdered form, and
then cooks them at temperatures between 700 C and 850 C.
Once the material is made, its structure is studied with a transmission
electron microscope and ultraviolet spectrums. Doing this allows Kuo to look at
ways to structurally improve the photocatalyst and its performance.
In addition to improving the material’s photocatalytic properties—which will
intensify reaction with the sunlight—Kuo focuses on increasing the material’s
surface area. An increased surface area means bigger and better reactions, and
a material with a high surface area and with high photocatalytic properties
could mean a bright future for solar gasoline and other alternative fuels.
Engineering a photocatalyst that efficiently splits water into hydrogen and
oxygen could also be a boon to fuel cell technology, Kuo says. Fuel cells
operate by essentially reversing the chemical reaction that’s used to split
water. Hydrogen is converted into electrical power, and water is given off as a
byproduct.
“Even though the mature technology of fuel cells is in the near future,
the source of hydrogen is still a question since most of the hydrogen sources now
are from petroleum,” Kuo says. “Therefore, water splitting using
photocatalysts is one of the solutions providing a new pathway to obtain
hydrogen.”
