Leaves are incredibly good at using CO2, sun, and water to generate energy, and so scientists have been eager to find a way to mimic that ability, but creating energy for humans to use. Imagine airplanes running on jet fuel made from sunlight and CO2, instead of using fuel made by drilling for oil.
New research published today in Nature Energy explains one new process for artificial leaf technology, inspired by photosynthesis, that can make carbon-neutral fuel at a low cost. “It mimics natural leaves,” says Yimin Wu, an engineering professor at the University of Waterloo who led the research. “We’re using carbon dioxide and water and sunlight as an input, and producing methanol and oxygen as a product.”
The process is 10 times more efficient than photosynthesis in a plant. The researchers are not the only scientists working on this type of technology, which is one way to make use of the billions of tons of excess CO2 in the atmosphere. Climeworks, a startup that pulls CO2 out of the air using direct air capture, is currently collaborating with others to study the feasibility of a new plant that will turn that CO2 into renewable jet fuel. Another startup, called Carbon Engineering, is also beginning to make jet fuel from captured CO2. Other researchers have argued that an artificial leaf could easily power a house. The technology often involves using electricity to split CO2 molecules. But the new process Wu’s team is studying avoids the use of electricity, which he says makes it easier to scale up since less infrastructure is necessary.
Wu’s team’s process uses a cheap red powder made of copper called cuprous oxide, which acts as a catalyst when it’s mixed with water and CO2. When a beam of white light is pointed at the mixture, it triggers a chemical reaction that produces oxygen and converts the CO2 to methanol. Next, the solution is heated, and the methanol is captured as it evaporates.
Wu plans to continue improving the efficiency of the technology, and will soon begin commercializing the process. Unlike startups like Carbon Engineering, he plans to work with CO2 captured from industry rather than directly from the air. “The CO2 itself is coming from waste gases from the steel industry, automotive industry, or even the oil drilling industry,” he says. “We can use this waste gas and convert it to useful chemical products.” The alternative fuel, whether it’s used instead of gasoline in cars or instead of jet fuel made from crude oil, should be cost-competitive.
As the process reduces emissions, it simultaneously reduces the need for more oil production. “It helps fight climate change, reducing CO2 emissions, but also provides sustainable energy,” Wu says.