Cambridge researchers have developed a fuel using only solar energy and carbon dioxide.
Researchers at the UK’s University of Cambridge have developed a means of making fuel using only solar power and carbon dioxide.
Over the past few years, the team have used an artificial leaf that can produce chemicals by photosynthesis. Recent developments have made it possible for this artificial leaf to directly produce ethanol and propanol.
The resultant fuels are much cleaner than fossil fuels and much more agriculturally ethical than biofuels.
Artificial leaves – how photosynthesis has been harnessed
Photosynthesis is, of course, the process through which plants convert sunlight and carbon dioxide into food. It takes place in the leaves of the plant.
A research group based at the university’s chemistry department led by Professor Erwin Reisner has used artificial leaves to produce sustainable, zero-carbon fuels through an artificial photosynthesis process.
Until recently, these artificial leaves were used to make simpler chemicals used to make plastics, fertilisers, and pharmaceuticals. They were also used to make syngas, a hydrogen and carbon dioxide mixture used to produce the fuels ethanol and propanol.
Now, thanks to a copper and palladium-based catalyst developed by Reisner’s group, the artificial leaves can directly produce these fuels without the need to produce syngas.
Researchers elsewhere have achieved similar results using electrical power, but this marks the first time such complex chemicals have been produced using only solar energy.
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An important step – the significance of this development
Bioethanol is much cleaner than petrol and other fossil fuels when burned. However, the concern with bioethanol is the amount of arable land taken up in its production.
For example, the US Department of Agriculture reports that 45% of all corn harvested in the country goes towards bioethanol production. This brings with it concerns that farmers worldwide might sacrifice food crops for biofuel production.
Reisner himself addressed the issue: “Biofuels like ethanol are a controversial technology, not least because they take up agricultural land that could be used to grow food instead”.
The importance of this research lies in the fact that, unlike bioethanol, no plants are required to produce these solar fuels and, thus, no agricultural land. Furthermore, unlike petrol and other fossil fuels, the solar fuels produce net zero carbon emissions.
The future – what the results mean going forward
This impressive technology remains at a laboratory scale, with much work ahead. However, the researchers noted that this work represents an important step away from a fossil fuel-based economy.
Their next step is to optimise the ‘chloroplasts’, or light absorbers, of their artificial leaves so that they can more efficiently absorb the sunlight. A better-optimised catalyst is also necessary for the process to work on a larger scale.
“Even though there’s still work to be done, we’ve shown what these artificial leaves are capable of doing”, said an optimistic Reisner.
“It’s important to show that we can go beyond the simplest molecules and make things that are directly useful as we transition away from fossil fuels”.
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