A new artificial leaf could help us combat climate change

Plants are among the most effective agents of carbon sequestration, a process whereby carbon dioxide is locked up from the atmosphere. During photosynthesis plants convert CO2 and water into oxygen and glucose thanks to the pigment chlorophyll in their leaves. They can do this by help of sunlight, which chlorophyll absorbs in order to facilitate chemical reactions within plant cells.

In order for more CO2 to be sequestered then, we can plant more plants. We can also boost plants’ ability to absorb CO2 from the air, such as by allowing them to grow bigger roots or by tweaking their efficiency at carbon capture.

A team of scientists from the University of Waterloo in Canada, California State University in the United States and the City University of Hong Kong has come up with another way we can capture CO2 from the atmosphere: by creating an artificial leaf that mimics the workings of real leaves.

Their artificial leaf converts CO2 into methanol, an alternative fuel that can then be put to good uses, they explain in a study published in the journal Nature Energy.

“We call it an artificial leaf because it mimics real leaves and the process of photosynthesis,” notes Yimin A. Wu, a professor of engineering at the Waterloo Institute for Nanotechnology who is the lead scientist behind the project, on which he has been working for the past four years. “A leaf produces glucose and oxygen. We produce methanol and oxygen.”

Their solution, if applied on a large enough scale, could both help mitigate the effects of climate change and provide us with a useful substitute for fossil fuels at the same time.

“The key to the process is a cheap, optimized red powder called cuprous oxide,” the researchers explain on the website of the University of Waterloo. “Engineered to have as many eight-sided particles as possible, the powder is created by a chemical reaction when four substances – glucose, copper acetate, sodium hydroxide and sodium dodecyl sulfate – are added to water that has been heated to a particular temperature.”

Mixed with water, the specially made power serves as the catalyst for a chemical reaction as carbon dioxide is pumped into it and a solar simulator shines a beam of white light into the chemical solution to power the reaction. The chemical reaction produces oxygen through a process that mimics photosynthesis.

At the same time, CO2  in the water-powder solution gets converted into methanol. The solution is then heated so that the methanol can be collected while it evaporates. “This is the chemical reaction that we discovered,” Wu says. “Nobody has done this before.”

The scientist says the invention could soon be applied on a commercial scale and deployed to convert CO2e collected from major greenhouse gas emitters such as power plants, vehicles and oil drills. “I’m extremely excited about the potential of this discovery to change the game,” Wu says. “Climate change is an urgent problem and we can help reduce CO2 emissions while also creating an alternative fuel.”