Scientists from the University of Cambridge have created an innovative “artificial leaf” that utilizes sunlight to convert water and carbon dioxide into ethanol and propanol, known as “drop-in” fuels. These fuels have the potential to directly power internal combustion engines without requiring any modifications, offering a low-emission alternative to gasoline.

The development of these solar fuels is significant as they produce net-zero carbon emissions, unlike fossil fuels, and are entirely renewable. Furthermore, unlike most bioethanol, their production does not compete with agricultural land used for food production.

The artificial leaf is constructed using multiple layers of copper, glass, silver, and graphite. It incorporates light absorbers similar to the molecules found in plants that capture sunlight, combined with a catalyst. This catalyst, resembling chlorophyll in natural leaves, consists of copper and palladium. When exposed to sunlight, the catalyst converts carbon dioxide into ethanol and propanol while transforming water into oxygen.

While the research team has long been exploring ways to harness photosynthesis for sustainable fuel production, previous artificial leaves were only capable of generating simple chemicals like syngas—a mixture of hydrogen and carbon monoxide used in the production of fuels, pharmaceuticals, plastics, and fertilizers.

The recent breakthrough enables scientists to produce clean ethanol and propanol directly without the need for syngas production, making the technology more practical and scalable. Unlike previous attempts that relied on electrical power, this marks the first time that an artificial leaf utilizing sunlight has successfully generated such complex chemicals.

Although the technology is currently limited to laboratory scale, the researchers believe their artificial leaves represent a crucial step toward transitioning away from a fossil fuel-based economy.

Professor Erwin Reisner, who led the research, emphasized the significance of the achievement: “Even though there’s still work to be done, we’ve shown what these artificial leaves are capable of doing. It’s important to demonstrate that we can go beyond the simplest molecules and produce directly useful substances as we move away from fossil fuels.”

The team’s future efforts will focus on optimizing the light absorbers to enhance sunlight absorption and improving the catalyst’s efficiency in converting sunlight into fuel. Additionally, they will work on scaling up the device to enable the production of larger volumes of fuel. In the future, this technology could potentially be integrated into vehicles, allowing them to produce clean fuel while on the move.

By Impact Lab