Artificial leaf and 'syngas'
Synthetic gas, also called 'syngas,' is a mixture of gases used as fuel in several industries. Syngas is made from hydrogen, carbon monoxide, and occasionally carbon dioxide, and can also be used to make several other chemicals we use on a wide scale, like synthetic petroleum, methanol, ammonia, and more.
It is primarily made from the gasification of materials like coal and municipal waste, which contribute to carbon emissions. The field of syngas production is about to change with the development of new technology that can create syngas using cleaner and more sustainable methods.
Researchers from Cambridge University's Christian Doppler Laboratory for Sustainable SynGas Chemistry were able to produce an artificial leaf that creates syngas from sunlight, water, and carbon dioxide—the results of which were published in a recent issue of Nature Materials.
How does the artificial leaf work?
In the past, other artificial leaf prototypes were only able to produce hydrogen. However, the Cambridge research team was able to produce syngas because of their unique combination of catalysts and materials.
The device works once immersed in water. There are two photocathodes (i.e. light absorbers) with a perovskite material configuration inside the artificial leaf. One light absorber uses the integrated cobalt catalyst to produce oxygen, while the other uses a chemical reaction with water to convert carbon dioxide into carbon monoxide and hydrogen. The result of both processes is the formation of syngas.
Choosing the catalyst was critical to the success of the device. Instead of conventional catalyst materials like platinum or silver, cobalt is found to be much more effective at converting carbon dioxide to carbon monoxide. Cobalt is also found in abundance around the world, making it a low-cost material that makes the technology more accessible.
Interestingly, the researchers found that even in low-light conditions, such as on rainy or overcast days, the device still works. Principal author Virgil Andrei notes that the artificial leaf can then be used anywhere in the world at any time.
The artificial leaf and the future of sustainability
Erwin Reisner, senior author of the study, shares his vision for the future of the material in a press release from Cambridge University:
"What we'd like to do next, instead of first making syngas and then converting it into liquid fuel, is to make the liquid fuel in one step from carbon dioxide and water... Being able to produce syngas sustainably would be a critical step in closing the global carbon cycle and establishing a sustainable chemical and fuel industry."
While still in its early stages and further development needed, this research is creating a great impact in the field of solar fuels.
The development of new technology like this artificial leaf is one of the first steps for the fuel and chemical industries to transition to more carbon-negative practices. With the massive demand for liquid fuels like syngas, this technology has the potential to make the shift towards circular carbon systems and a more sustainable future more feasible.