Cars soon could be powered by fuels produced using only sunshine. A revolutionary new clean fuel that is made from the energy of the sun has been developed by scientists at the University of Cambridge in England.
To develop the fuel the researchers used the power of photosynthesis—the process by which plants use sunlight to create foods from carbon dioxide and water.
The big difference between these fuels and fossil fuels is that the new fuels produce net zero carbon emissions. They also are entirely renewable and do not cause any agricultural land to be taken away from the production of food. In addition, the fuels, such as ethanol and propanol, are high in energy and can easily be transported and stored.
Significant Step Away From Fossil Fuels
Although the technology is still at the stage of being developed only in a laboratory, the researchers say that the “artificial leaves” used in producing the fuel are a significant step in transitioning away from an economy that is based on fossil fuels.
Bioethanol such as that produced using the newly developed process is favored as a cleaner alternative to gasoline because it is made from plants instead of from fossil fuels. Most trucks and cars in the United States run on gas that contains up to 10% ethanol.
The reason that biofuels such as ethanol are controversial today is that they take up agricultural land that could instead by used to grow food, explains Professor Erwin Reisner, who led the research into the new fuel.
About 45% of all corn that is grown in the United States is used to produce ethanol, according to the U.S. Department of Agriculture.
The newly developed fuel, however, is produced using artificial leaves and therefore does not use up existing agricultural land or crops that could instead be used for food.
Developed Over Years
For several years a research group led by Reisner has been developing zero-carbon sustainable fuels that are created by photosynthesis using artificial leaves.
So far these artificial leaves have been able to produce only simple chemicals, such as syngas, which is a mixture of carbon monoxide and hydrogen used to produce pharmaceuticals, fuels, fertilizers, and plastics.
In order for the technology to be more practical, however, it would need to produce chemicals that are more complex. The fuels would also need to be produced directly from sunlight in a single step.
That step now has been taken. The artificial leaves can produce clean ethanol and propanol without taking the intermediate step of producing syngas. The scientists developed a palladium- and copper-based catalyst that was optimized to enable the artificial leaves to produce chemicals that are more complex such as ethanol and propanol.
Using sunlight on the artificial leaves and obtaining liquid fuel from water and carbon dioxide is an “amazing bit of chemistry,” says Dr. Moriar Rahaman, first author of the study in which the development is outlined.
Normally, he adds, when you seek to convert carbon dioxide into another chemical product by using an artificial leaf as a device, you nearly always obtain syngas or carbon monoxide.
In this case, however, the scientists have been able to develop a liquid fuel that is practical just by using the power of the sun.
Proof of Concept
The device is an exciting one that opens up entire new avenues in their work, Rahaman says.
Right now the device is what scientists call “proof of concept.” The researchers are working on optimizing the light absorbers in order that they can absorb sunlight more effectively.
They are also working on improving the catalyst in order that it will be able to change more sunlight into fuel.
These are essentially enhancements to the way in which the system works. The important aspect is that the system works. Scientists are now looking at ways to make it work effectively to produce large amounts of fuel. The breakthrough has been made. It must now be refined.
Although work still has to be done, the scientists have shown what the artificial leaves are capable of doing, Reisner says. It is vital to show that they can move past the simple molecules in order to make things that are directly useful as we move away from fossil fuels, he adds.
The study is published in the journal Nature Energy.