As deforestation continues to diminish the number of trees, vital for absorbing carbon dioxide produced by burning fossil fuels, scientists are looking for ways to replicate natural processes to reduce pollution levels. One such solution being developed is artificial leaves that are able to perform photosynthesis.

Researchers have created devices that mimic the natural process of photosynthesis, working like real leaves to use water and carbon dioxide from the air to produce carbohydrates using energy from the sun.

This is achieved through the use of a light absorber coated with catalysts that converts carbon dioxide to carbon monoxide and converts water to oxygen using sunlight.

However, up until now, the artificial leaves only worked in the laboratory as they rely on pure, pressurised carbon dioxide from tanks. When carbon dioxide levels were diluted, such as in the atmosphere artificial photosynthesis was not effective.

However, researchers from the University of Illinois at Chicago have come up with a solution that could mean the leaves can be used outside the lab.

How artificial leaves mimic nature

When an artificial leaf is encapsulating inside a transparent capsule made of a semi-permeable membrane and filled with water, the membrane allows water from inside to evaporate out when warmed by sunlight. As water passes out through the membrane, it pulls in carbon dioxide from the air even though it is at a lower concentration, working like a natural leaf.

Inside the leaf, carbon dioxide is converted to carbon monoxide, which can then be used as a basis for the creation of various synthetic fuels.

Researchers have calculated that 360 leaves, each 1.7m long and 0.2m wide, would produce close to a half-ton of carbon monoxide per day that could be used as the basis for synthetic fuels. Oxygen is also produced and can either be collected or released into the surrounding environment.

Furthermore, artificial photosynthesis also reduces carbon dioxide levels, and is thought to be at least 10 times more efficient than natural leaves at converting it to fuel.

If the leaves were covering a 500m2 area then it is thought they would be able to reduce carbon dioxide levels by 10% in the surrounding 100m.

Meenesh Singh, assistant professor of chemical engineering in the UIC College of Engineering and corresponding author on the paper said:

“Our conceptual design uses readily available materials and technology, that when combined can produce an artificial leaf that is ready to be deployed outside the lab where it can play a significant role in reducing greenhouse gases in the atmosphere.”