Scientists are accelerating efforts to convert carbon dioxide (CO₂) into usable fuels using electricity, recycling atmospheric carbon rather than extracting it from the ground.
A team led by Andrew Barnabas Wong at the National University of Singapore has shown that waste materials such as seafood shells and plant matter can dramatically improve the efficiency with which CO₂ is converted into fuel. The findings were published in Nature Energy.
The team focused on copper, a widely used catalyst for converting CO₂ into fuels such as ethylene and ethanol. These fuels are valuable because they are used in plastics, chemicals, and energy systems. Today, they mostly come from petroleum refining.
But copper has a challenge. It does not always produce the desired fuels efficiently. Often, it ends up producing hydrogen gas instead, reducing the usefulness of the process.
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To solve this, scientists usually add special coatings to control reactions at the copper surface. These coatings are often made from Nafion, a synthetic material belonging to the PFAS group of chemicals. These are also called ‘forever chemicals’ because they do not break down easily and are linked to health risks.
Professor Wong’s team took a very different approach. They created ultra-thin coatings, just two to five nanometers thick, using biopolymers. These materials come from natural sources such as chitin and chitosan, which are found in crustacean shells, as well as cellulose from wood and plant waste.
In their experiments, the coated copper catalysts achieved up to 90% selectivity for multicarbon products. This means most of the electrical energy went into producing useful fuels rather than unwanted byproducts.
Even more importantly, this performance held strong under industrial conditions. At a high current density of 1.6 amperes per square centimeter, the system maintained 90% selectivity.
When pushed further to 2.2 A/cm², a level that usually reduces efficiency, it still delivered 83%. These numbers are among the best reported for copper-based CO₂ conversion.
The team also tested a tandem system. They combined copper nanoparticles with silver nanoparticles to further enhance performance. This setup helped maximize the production of multicarbon fuels.
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How Shell Coating Works
The success of these coatings comes from how they change the environment around the catalyst. Using advanced tools, the researchers found that the biopolymer layer pulls CO₂ molecules toward the surface. At the same time, it limits the movement of water around the catalyst. This reduces unwanted reactions that produce hydrogen.
The coating also improves how ions move during the reaction. Together, these effects guide the process toward producing fuels like ethylene and ethanol.
“Our work shows new ways to improve electrochemical CO₂ conversion,” Wong said. “We can make fuels without oil or refining.”
He added that the team has shown that expensive and harmful materials can be replaced. “We can use cellulose, chitin, and chitosan instead of forever chemicals,” he said.
The cost advantage is significant. Nafion is expensive and difficult to produce. In contrast, chitosan, a material derived from shell waste, costs about $50 per kilogram. That is roughly one-thousandth the cost of Nafion by weight.
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The team also showed that these biopolymers can fully replace Nafion as a binding material in the electrode. In one test, a cellulose-coated copper catalyst bound with chitin achieved 95% selectivity for multicarbon products.
This means the new approach is not just cleaner, but also more affordable. At a time when governments are tightening regulations on PFAS, this could help industries transition faster to safer materials.
Electrochemical CO₂ conversion is still developing. But it is becoming a key part of future energy systems. The idea is simple: use renewable electricity to turn CO₂ into fuels and chemicals, reducing the need for fossil resources.
If powered by clean energy, the process could even become carbon-negative. That means it would remove more CO₂ from the atmosphere than it produces.
The new biopolymer coating supports this vision. It improves efficiency and reduces reliance on harmful chemicals, all while using abundant waste materials.
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Wong emphasized that the findings challenge old assumptions. “People believed materials like Nafion were essential,” he said. “But our work shows a completely different path.”
The team is now working to refine the technology further. One goal is to control the ratio of products like ethanol and ethylene. Another is to improve long-term stability so the system can run continuously without interruption.
“More promising developments are in the pipeline,” Wong said.
As the world searches for alternatives to fossil fuels, solutions like this may play a key role. Turning waste into high-performance materials and CO₂ into fuel can reshape how energy is produced in the years ahead.
