Plants have long been classified as self-sustaining organisms, meaning they can work with elements from the environment to create their own food. Soon, they may have to share this rare distinction with an artificial photosynthesis system—a creation of Richard Watt, faculty member in the Department of Chemistry and Biochemistry. This new system may prove to be a valuable source of renewable electrical energy in the near future.
Nature thrives on renewable energy. Elements work together in never-ending cycles to produce the power needed to keep plants growing and producing. Photosynthesis is an example of conservative, efficient energy systems at work.
“In photosynthesis, light strikes chlorophyll and an electron gets excited to a higher energy state,” Watt explained. “Then another molecule grabs the electron and pulls it away. Now, that electron works like water in a hydroelectric dam. It falls through a molecular energy-level system that creates energy the plant can use. But the original molecule–the one that had the electron that got excited–now wants one back. So some other molecule nearby has to donate electrons to that molecule. They cycle.”
Studying this cycle, Watt identified ferritin as an element with properties that could simulate nature’s miracle. Ferritin is a round, hollow protein that can fit thousands of iron atoms inside its shell and, just like chlorophyll, light affects the energy levels of its electrons.
“We’re trying to build an artificial photosynthesis system by shining light on ferritin,” Watt said. “When you shine light on it, electrons get excited just like in photosynthesis. And those electrons can be used for energy or may be transferred into batteries for energy storage.”
Like the electrons that keep cycling in plants, ferritin keeps giving and taking electrons in a continuous stream of movement as long as light is present.
The main difference between Watt’s system and that of nature is their respective end goals. While plants are working to convert energy into food storage, Watt’s model is simply working to harvest raw energy.
“In a plant, sunshine excites electrons and the energy from the excited electrons is used to build sugars. We would short-circuit that system and use the electrons to make an electrical cell,” he said.
To make this project even more ideal, glucose can be used as the electron donor to ferritin. This means that waste products from farms, such as corn stalks that are rich in glucose, may be put to good use as natural fuel for an artificial photosynthesis system.
The world consumes large amounts of energy. Many sources of natural power have been and are being developed. With the potential to produce energy more efficiently than other current sources, Watt’s project may prove to be a prominent addition to the energy options available.