Researchers have split water into hydrogen and oxygen using a technique inspired by photosynthesis, the process through which plants convert sunlight into energy.


Photosynthesis is among the most important reactions on the planet because it produces nearly all of the world's oxygen. It also inspires techniques that can potentially lead to the production of clean energy.

Plants "split" water molecules into oxygen and hydrogen during this process and hydrogen holds potential as a zero-emission fuel that can provide an unlimited source of renewable energy.

Although artificial photosynthetic techniques have been around for a while, these have not been used to generate renewable energy since the methods require catalyst materials that are expensive and toxic.

Semi-Artificial Photosynthesis

In a new study published in the journal Nature Energy, researchers reported a method to split water into hydrogen and oxygen using sunlight.

Erwin Reisner, from St John's College, at the University of Cambridge, and colleagues used semi-artificial photosynthesis to produce and store solar energy.

Instead of using catalyst materials with considerable drawbacks, the researchers used natural enzymes along with man-made technologies to convert water into hydrogen and oxygen. The enzyme is called hydrogenase, which is present in algae. Researchers said that hydrogenase can reduce protons into hydrogen.

"Semi-artificial photosynthesis combines the strengths of natural photosynthesis with synthetic chemistry and materials science to develop model systems that overcome nature's limitations, such as low-yielding metabolic pathways and non-complementary light absorption by photosystems I and II," the researchers wrote in their study published on Sept. 3.

The method overcomes some of the limitations of purely artificial photosynthesis techniques. It is also more efficient than natural sunlight when it comes to absorbing solar light.

"Compared to the natural pathway, this new system makes wider use of the solar spectrum, delivers high conversion yields, and bypasses several competing metabolic steps, which is not achievable using synthetic biology or materials science alone," Reisner said.

Proof-Of-Principle Method

The system holds promise in revolutionizing systems used for producing renewable energy but the researchers said that technique is still a proof-of-principle. The method is currently still too fragile for use in a real-world setting. The researchers nonetheless hope that they would be able to refine the concept.

"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," said study researcher Katarzyna Sokół, from St John's College.

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