Apart from nuclear energy, all energy sources are either directly or indirectly dependent on the Sun. Researchers have been trying to get more and more energy from our star over the years, and many teams have been attempting to create fuels from sunlight. The latest took a figurative leaf from plants and mimicked photosynthesis to create fuel.
As reported in Nature Energy, researchers have taken a substantial step forward in using sunlight to split water molecules into hydrogen and oxygen. While artificial photosynthesis has been performed for decades, the method used in this study is a type of semi-artificial photosynthesis, where biological and inorganic systems are made to work together. The method uses enzymes to achieve the reaction and is able to absorb more sunlight than natural photosynthesis.
"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 percent of what it could potentially convert and store," lead author Katarzyna Sokół, from the University of Cambridge, said in a statement.
The team used a natural but dormant process found in algae. The algae have an enzyme called hydrogenase that can split water. The process is no longer useful for survival but it is useful to us. The researchers were able to successfully use hydrogenase with a photosynthetic system for the first time. With that, they achieved semi-artificial photosynthesis driven exclusively by solar power.
“It’s exciting that we can selectively choose the processes we want, and achieve the reaction we want which is inaccessible in nature. This could be a great platform for developing solar technologies,” Sokół added. “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.”
The team is confident that this work is a milestone in the emerging field of semi-artificial photosynthesis. Many groups are shifting away from artificial photosynthesis due to cost and the fact that the products required to make reactions efficient are often toxic. Semi-artificial solutions, like the new technique, offer a safer and potentially cheaper toolbox to build solar energy conversion systems in the future.