Researchers from the University of Cambridge have developed a new method to produce chemicals using solar power, aiming to reduce the chemical industry's reliance on fossil fuels. The industry is responsible for about 6% of global carbon emissions due to its use of fossil fuel feedstocks.
The Cambridge-led team created a hybrid device that uses light-harvesting organic polymers and bacterial enzymes to convert sunlight, water, and carbon dioxide into formate, which can then be used in further chemical processes. This approach mimics photosynthesis and does not require external power or toxic materials.
The research was published in the journal Joule. It marks the first time organic semiconductors have been used as the light-absorbing part in such biohybrid devices, potentially opening up more sustainable ways to make chemicals used in products like plastics and pharmaceuticals.
Professor Erwin Reisner from Cambridge’s Yusuf Hamied Department of Chemistry said: “If we’re going to build a circular, sustainable economy, the chemical industry is a big, complex problem that we must address. We’ve got to come up with ways to de-fossilise this important sector, which produces so many important products we all need. It’s a huge opportunity if we can get it right.”
Previous designs often depended on synthetic catalysts or inorganic semiconductors that degraded quickly or contained toxic elements. Co-first author Dr Celine Yeung said: “If we can remove the toxic components and start using organic elements, we end up with a clean chemical reaction and a single end product, without any unwanted side reactions. This device combines the best of both worlds – organic semiconductors are tuneable and non-toxic, while biocatalysts are highly selective and efficient.”
The device also integrates enzymes from sulphate-reducing bacteria and avoids unsustainable additives by using a helper enzyme embedded in porous titania. Dr Yongpeng Liu explained: “It’s like a big puzzle. We have all these different components that we’ve been trying to bring together for a single purpose. It took us a long time to figure out how this specific enzyme is immobilised on an electrode, but we’re now starting to see the fruits from these efforts.”
Yeung added: “By really studying how the enzyme works, we were able to precisely design the materials that make up the different layers of our sandwich-like device. This design made the parts work together more effectively, from the tiny nanoscale up to the full artificial leaf.”
Tests showed that the artificial leaf produced high currents and maintained efficiency for over 24 hours—more than twice as long as earlier versions.
Reisner said: “We’ve shown it’s possible to create solar-powered devices that are not only efficient and durable but also free from toxic or unsustainable components. This could be a fundamental platform for producing green fuels and chemicals in future – it’s a real opportunity to do some exciting and important chemistry.”
The research received support from several organizations including Singapore's Agency for Science, Technology and Research (A*STAR), the European Research Council, Swiss National Science Foundation, Royal Academy of Engineering, and UK Research and Innovation (UKRI).