Your next car could be powered on SUNSHINE! Solar-powered tech converts CO2 and water into fuel
Electric vehicles are billed as the future of zero emissions transport, but the ultimate eco-friendly car could be powered on sunshine.
Researchers have created an ‘artificial leaf’ that uses sunlight to covert water and carbon dioxide to low-emissions fuels – ethanol and propanol.
If this sounds familiar, the artificial leaf mimics photosynthesis, the famous process used by plants to create their energy.
In the lab, the experts submerged the leaf in CO2-infused water before shining light on it to trigger the reaction and create the green fuels.
But in the future, cars could be built with the tech to take surrounding sunlight, CO2 and water vapor in the air and produce the fuels on-the-go.
Electric vehicles are billed as the future of zero emissions transport, but the ultimate eco-friendly car could be powered on sunshine
Researchers have created an ‘artificial leaf’ that uses sunlight to covert water and carbon dioxide to low-emissions fuels – ethanol and propanol. The artificial leaf is pictured here attached to a metal rod. In the future, it could be part of a car’s apparatus to produce clean fuel on-the-go
The technology is described in a new study led by University of Cambridge researchers and published in the journal Nature Energy.
How does it work?
Researchers made their ‘artificial leaf’ from multiple layers including copper, glass, silver and graphite.
– The leaf also includes a catalyst that sparks the reaction, made from two elements (copper and palladium).
– In the presence of sunlight, the catalyst coverts CO2 to ethanol and propanol, and the water into oxygen.
‘Shining sunlight on the artificial leaves and getting liquid fuel from carbon dioxide and water is an amazing bit of chemistry,’ said study author Dr Motiar Rahaman.
‘In this work, we developed an artificial leaf device to generate multicarbon alcohols from CO2 and water using sunlight as the sole energy source.’
Researchers made their ‘artificial leaf’ from multiple layers including copper, glass, silver and graphite.
The artificial leaf contains light absorbers – similar to the molecules in plants that harvest sunlight – which are combined with a catalyst.
This catalyst (which is akin to chlorophyll, the catalyst for photosynthesis in a real leaf) is made from two elements, copper and palladium.
In the presence of sunlight, the catalyst coverts CO2 to ethanol and propanol, and the water into oxygen.
‘The alcohol products can be extracted from the reaction medium and then can be used in a car,’ Dr Rahaman told MailOnline.
While the technology is still at laboratory scale, the scientists say their ‘artificial leaves’ are an important step in the transition away from fossil fuels that are currently used in cars – namely petroleum.
Pictured, a photoreactor containing the artificial leaf and CO2-infused water. This is a scaled-down lab version of what the technology could be like. In the future, cars could be built to take surrounding sunlight, CO2 and water vapor in the air and produce the fuel on-the-go
The Cambridge researchers made their ‘artificial leaf’ from multiple layers including copper, glass, silver and graphite, as well as copper and palladium for the catalyst
Already, ethanol is used as a clean fuel in cars and is commonly made from biomass such as corn or sugarcane.
It’s touted as a greener alternative to petrol, since it is made from plants instead of fossil fuels.
Many cars and trucks on the road today run on petrol containing up to 10 per cent ethanol (sold at petrol stations as E10 fuel).
One problem, however, is that production of ethanol takes up agricultural land that could be used to grow food instead.
According to the US Department of Agriculture, almost 45 percent of all corn grown in the US is used for ethanol production.
And the more demand for this eco-friendly ethanol grows, the more land that is required.
Fortunately, the Cambridge team’s technology offers an alternative ethanol production method.
In the future, the lead could be part of a car’s apparatus to produce clean fuel on-the-go if it can extract the water and CO2 from surrounding air while exposed to sunlight.
However, the team cautions that the device is at the moment only a proof of concept with ‘modest efficiency’.
‘Even though there’s still work to be done, we’ve shown what these artificial leaves are capable of doing,’ said study author Professor Erwin Reisner at Cambridge, who led the research.
‘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.’
Back in 2019, the Cambridge team described using their artificial leaf technology to produce synthetic gas or ‘syngas’ – a mixture of hydrogen and carbon monoxide that is used to produce fuels, pharmaceuticals, plastics and fertilisers.
Currently, cars and trucks on the road today run on petrol containing up to 10 percent ethanol (known as E10 fuel).
But now, the artificial leaf can directly produce clean ethanol and propanol without the need for the intermediate step of producing syngas.
What’s more, ethanol and propanol are eco-friendly fuels that have a high energy density and can be easily stored or transported.
‘Normally, when you try to convert CO2 into another chemical product using an artificial leaf device, you almost always get carbon monoxide or syngas,’ said Dr Rahaman.
‘But here, we’ve been able to produce a practical liquid fuel just using the power of the sun.
‘It’s an exciting advance that opens up whole new avenues in our work.’
The researchers are now working to improve the light absorbers so that they can better absorb sunlight as well as the catalyst so it can convert more sunlight into fuel.
Further work will also be required to make the device scalable so that it can produce large volumes of fuel – although it’s unclear how much this would cost.
HOW DOES PHOTOSYNTHESIS WORK?
Photosynthesis is a chemical process used by plants to convert light energy and carbon dioxide into glucose for the plant to grow, releasing oxygen in the process.
The leaves of green plants contain hundreds of pigment molecules (chlorophyll and others) that absorb light at specific wavelengths.
When light of the proper wavelength strikes one of these molecules, the molecule enters an excited state—and energy from this excited state is shuttled along a chain of pigment molecules until it reaches a specific type of chlorophyll in the photosynthetic reaction center.
Schematic showing how photosynthesis works. One of the most important steps in photosynthesis is the splitting of water to release hydrogen and oxygen atoms, forming glucose sugar for the plant to grow and releasing oxygen as a byproduct.
Here, energy is used to drive the charge-separation process required for photosynthesis to proceed.
The electron ‘hole’ left behind in the chlorophyll molecule is used to ‘split’ water to oxygen.
Hydrogen ions formed during the water-splitting process are eventually used to convert carbon dioxide to glucose energy, which the plant used to grow.