The device is an important step towards achieving artificial photosynthesis – a process that neglects the ability of plants to convert sunlight into energy.
It is based on advanced ‘photosheet’ technology and converts sunlight, carbon dioxide and water into oxygen and formic acid – a storable fuel that can be used directly or converted into hydrogen.
The results represent a new method for the conversion of carbon dioxide into clean fuels. The wireless device could be scaled up and used on ‘energy’ farms similar to solar farms, and produced clean fuel with sunlight and water.
Harvesting solar energy to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and transition away from fossil fuels. However, it is challenging to produce these clean fuels without unwanted by-products.
“It has been difficult to achieve artificial photosynthesis with a high degree of selectivity, so you can convert as much of the sunlight as possible into the fuel you want, instead of staying with a lot of waste,” said first author Dr. . Qian Wang of Cambridge’s Department of Chemistry.
“In addition, storage of gaseous fuels and separation of by-products can be complicated – we want to get to the point where we can produce a clean liquid fuel that can also be easily stored and transported,” said Professor Erwin Reisner, the paper senior author.
In 2019, researchers from Reisner’s group developed a solar reactor based on an ‘artificial blade’ design, which also uses sunlight, carbon dioxide and water to produce a fuel known as syngas. The new technology looks and behaves very much like the artificial leaf, but works in a different way and produces formic acid.
While the artificial blade used solar cell components, the new device did not need these components and relied solely on photocatalysts embedded in a blade to produce a so-called photocatalyst blade. The blades are composed of semiconductor powders, which can be prepared easily and cost-effectively in large quantities.
In addition, this new technology is more robust and produces clean fuel that is easier to store and shows potential for scale production of fuel products. The test unit is 20 square centimeters in size, but researchers say it should be relatively easy to scale it to several square meters. In addition, the formic acid can be built up in solution, and chemically converted into different types of fuel.
