A new device is able to take in sunlight, carbon dioxide and water to create a new carbon-neutral fuel without any outside source of electricity, its developers claim.
University of Cambridge experts behind the device say it uses a form of ‘artificial photosynthesis’ – the process used by plants to convert sunlight into energy.
The device is based on an advanced ‘photosheet’ technology and converts sunlight, carbon dioxide and water into oxygen and formic acid – a storable fuel.
This type of fuel can be either used directly in specially developed generators or by converting it into hydrogen, according to the Cambridge team.
The wireless device could be scaled up and used on energy ‘farms’ similar to solar farms, producing clean fuel using nothing but sunlight and water as its inputs.
A new device is able to take in sunlight, carbon dioxide and water to create a new carbon-neutral fuel without any outside source of electricity, its developers claim
Harvesting solar energy to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and transition away from fossil fuels, experts claim.
However, it is challenging to produce these clean fuels without unwanted by-products that are costly and complicated to remove.
‘It’s been difficult to achieve artificial photosynthesis with a high degree of selectivity, so that you’re converting as much of the sunlight as possible into the fuel you want, rather than be left with a lot of waste,’ said first author Dr Qian Wang.
Senior author, Professor Erwin Reisner, said storage of gaseous fuels and the separation of by-products can be a complicated process.
‘We want to get to the point where we can cleanly produce a liquid fuel that can also be easily stored and transported,’ Professor Reisner added.
In 2019, researchers from Reisner’s group developed a solar reactor based on an ‘artificial leaf’ design, which also uses sunlight, carbon dioxide and water to produce a fuel, known as syngas.
The new technology looks and behaves quite similarly to the artificial leaf but works in a different way and produces formic acid.
While the artificial leaf used components from solar cells, the new device doesn’t require these components and relies solely on photocatalysts embedded on a sheet to produce a so-called photocatalyst sheet.
The sheets are made up of semiconductor powders, which can be prepared in large quantities easily and cost-effectively.
In addition, this new technology is more robust and produces clean fuel that is easier to store and shows potential for producing fuel products at scale.
Dr Qian Wang (pictured) and her colleagues have developed a standalone device that converts sunlight, carbon dioxide and water into a carbon-neutral fuel, without requiring any additional components or electricity
The test unit is about three square inches in size, but the researchers say that it should be relatively straightforward to scale it up to several square feet.
In addition, the formic acid can be accumulated in solution, and be chemically converted into different types of fuel.
‘We were surprised how well it worked in terms of its selectivity – it produced almost no by-products,’ said Wang. ‘Sometimes things don’t work as well as you expected, but this was a rare case where it actually worked better.’
Thee device is easy to make and relatively stable, according to the study authors.
The test unit is about three square inches in size, but the researchers say that it should be relatively straightforward to scale it up to several square feet
While this technology will be easier to scale up than the artificial leaf, the efficiencies still need to be improved before any commercial deployment can be considered.
The researchers are experimenting with a range of different catalysts to improve both stability and efficiency.
The current results were obtained in collaboration with the team of Professor Kazunari Domen from the University of Tokyo, a co-author of the study.
The researchers are now working to further optimise the system and improve efficiency and see if they can produce different solar fuels.
‘We hope this technology will pave the way toward sustainable and practical solar fuel production,’ said Reisner.
The findings have been published in the journal Nature Energy.
RESEARCHERS USE ‘ARTIFICIAL’ TREES CLEAN THE AIR IN CITIES
By keeping mosses in a container, such as those built by CityTrees, the conditions can be carefully controlled to ensure the plant is always thriving and therefore performing at optimum air filtration
CityTrees – also known as artificial trees – use living plants and different types of mosses to capture toxins and remove pollutants from the surrounding environment to produce clean air.
Mosses, despite being a more primitive lifeform than most trees and flowers, conduct photosynthesis.
This allows them to soak up carbon dioxide – a greenhouse gas – from the atmosphere and produce oxygen.
They can also harbour friendly bacteria which further helps trap pollutants.
By keeping mosses in a container, such as those built by CityTrees, the conditions can be carefully controlled to ensure the plant is always thriving and therefore performing at optimum air filtration.
Each self-sustaining CityTree contains a water tank, irrigation systems and sensors to monitor plant growth and ensure they are healthy. The technology is powered by a combination of on-board solar panels and internal batteries.
Each CityTree which has the pollution-reduction benefits of 275 normal trees.
Similar structures have previously been employed in other cities — including Berlin and Hong Kong — along with temporary trials across London.
Plants also help soak up air pollutants directly. Studies have found that the worst offending air pollution for human health is PM2.5 or airborne fine particulate matter.
These particulates are dangerous because they can get deep into your lungs, or even pass into your bloodstream.
Particulates are found in higher concentrations in urban areas, particularly along main roads.
One study from researchers at Beijing Forestry University in 2017 found ‘foliage acts as a bio-filter of air pollution and improves air quality due to the leaves’ rough texture and large contact area’.
But the issue with relying on regular trees and plants to filter the air and remove carbon dioxide and pollutants is that they themselves are highly dependent on the environment.
If they are not thriving due to disease, drought or vandalism, they will fail to clean the air effectively.
Mosses, despite being a more primitive lifeform than most trees and flowers, conduct photosynthesis. This allows them to soak up carbon dioxide – a greenhouse gas – from the atmosphere and produce oxygen. Plants also directly soak up pollutants