BYU team finds new way to harvest solar energy

Published: Friday, Jan. 28 2011 10:58 p.m. MST

Richard Watt and his chemistry students suspect a common protein could react with sunlight and harvest its energy.

Mark A. Philbrick, BYU

PROVO — Each winter day as Robert Hilton drives down the hill from his home in Orem to BYU campus, he is confronted with the thick, blanket-like layer of smog that settles over the valley.

Someday, the BYU Ph.D candidate would like to see green technologies — like the one he, BYU professor Richard Watt and a few other students recently discovered — as a source of cleaner energy.

"I don't think any single technology would take over, it will be a lot of different things," he said. "But hopefully, this could be one of those things."

Their project is still in the beginning stages, but so far the team has been able to "mimic" photosynthesis by using a protein, citric acid and gold atoms.

In plants, photosynthesis begins when light hits the leaves and excites electrons. That excited electron is then useful for work and helps generate sugars and starches to help the plant grow, explained BYU chemistry professor Richard Watt. "When we excite an electron," he continued, "We can use it for electricity to run a motor, turn on a light, charge a battery."

In the BYU study, which was recently published in the Journal of Nanoparticle Research, Watt and his students set up their "plant" in a vial with the protein ferritin as a catalyst, citrate from oranges and the gold atoms.

When they exposed the solution to sunlight, ferritin forced citrate to give up an electron, which was then absorbed by the gold, which formed gold nanoparticles — all in about 20 minutes, Watt said.

The team knew an energy transfer had taken place because the yellow mixture turned a deep purple. It's a property called "plasmon resonance," which means tiny nanoparticles appear a different color than when they're larger. (Silver does the same thing and becomes a bright yellow color, Watt explained.)

The next logical step, Hilton explained, will be to attach the ferritin to an electrode and develop a solar fuel cell to actually harvest the energy out of the system.

Another part of expanding this on a broader scale would be finding an abundant biomass source, such as corn stalks, or grass clippings that could be recycled to provide a ready source of electrons, rather than the citrate, Watt said.

Harvesting energy from the sun is not a new idea and solar panels do a similar thing, Watt said, but in a 'solid-state chemistry' form. Watt's system combines solar cell chemistry with a biomass in a liquid state.

"It's still in the early stages, but the developmental part is very important in order to build upon this to make future discoveries," Watt said. "(People) are probably not going to ever see a ferritin fuel cell powering their house or their cars, but something maybe two steps down the road from this preliminary research might be something that's useful."

For recent BYU graduate, Jeremiah Keyes, another co-author on the paper, the experience has already proven useful, first by providing meaningful application to his classes and then helping him secure a spot in the Ph.D program in the Department of Biochemistry and Molecular Biology at Wake Forest University.

"From working with Dr. Watt and his group I definitely want to pursue my career in science, get a Ph.D and continue from there," Keyes said. "(At BYU) I didn't just learn from books, I started being able to think as a scientist."

e-mail: sisraelsen@desnews.com

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