Photosynthesis, the process plants use to convert sunlight into energy, has sustained them for millennia. Now, scientists are looking to improve on nature’s efforts with a mixture of biological components and man-made technologies in the hopes of creating new possibilities in solar energy storage.
“Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store,” says Katarzyna Sokól, first author of the paper and a PhD student at St John’s College describing the technique in Nature Energy, in a press statement.
“Semi-artificial photosynthesis combines the strengths of natural photosynthesis with synthetic chemistry and materials science to develop model systems that overcome nature’s limitations,” the group writes in their abstract.
Artificial photosynthesis has been a dream for over a century, first anticipated by Italian chemist Giacomo Ciamician in 1912 who imagined using the sun’s energies to power cars. The “photochemistry of the future,” as Ciammician referred to it, was later realized by a process known as photocatalytic water splitting, in which an catalyst could induce photosynthesis using only water.
However these catalysts are often toxic. And what’s more, they’re expensive. So instead of using a traditional catalyst, the team from Cambridge in England and the Ruhr-Universität Bochum in Germany turned to enzymes found within algae. It’s an enzyme that has remained dormant within the plant for millennia.
“Hydrogenase,” Sokol explains, discussing the enzyme in question, “is capable of reducing protons into hydrogen. During evolution this process has been deactivated because it wasn’t necessary for survival but we successfully managed to bypass the inactivity to achieve the reaction we wanted – splitting water into hydrogen and oxygen.”
Using hydrogenase and what’s known as photosystem II, the first protein complex in the light-dependent reactions of oxygenic photosynthesis, the team has become first to successfully create semi-artificial photosynthesis driven entirely by solar power. It’s the start of a process that Sokol and the rest of the team hopes will lead to new venues of solar energy storage.
“It’s exciting that we can selectively choose the processes we want,” she says, and achieve the reaction we want which is inaccessible in nature. This could be a great platform for developing solar technologies. The approach could be used to couple other reactions together to see what can be done, learn from these reactions and then build synthetic, more robust pieces of solar energy technology.”
Previously published by: Popular Mechanics USA