A new technology that captures carbon dioxide from the air and transforms it into fuel using only sunlight could help reshape our approach to both climate change and energy production. The innovation, developed by researchers at the University of Cambridge, operates much like an artificial plant, working day and night to convert atmospheric carbon dioxide into useful fuels.
The device consists of a dual-chamber system that works in a daily cycle โ capturing carbon dioxide from the air at night and converting it into synthesis gas (syngas) during the day using concentrated sunlight. This syngas can then be transformed into various fuels and chemicals, potentially offering a sustainable alternative to fossil fuels.
โWhat if instead of pumping the carbon dioxide underground, we made something useful from it?โ said Dr. Sayan Kar from Cambridgeโs Yusuf Hamied Department of Chemistry. โCO2 is a harmful greenhouse gas, but it can also be turned into useful chemicals without contributing to global warming.โ
The technology represents a significant departure from conventional carbon capture and storage (CCS) methods, which typically require substantial energy input and face ongoing questions about the long-term safety of underground CO2 storage.
โAside from the expense and the energy intensity, CCS provides an excuse to carry on burning fossil fuels, which is what caused the climate crisis in the first place,โ said Professor Erwin Reisner, who led the research. โCCS is also a non-circular process, since the pressurised CO2 is, at best, stored underground indefinitely, where itโs of no use to anyone.โ
The systemโs operation mirrors the natural process of photosynthesis, but with enhanced efficiency. During nighttime hours, specialized filters containing silica and polyamine materials act like a sponge, absorbing CO2 from the air. When daylight arrives, concentrated sunlight heats the captured CO2 while simultaneously powering its conversion into syngas using a novel catalyst system.
The researchers engineered the device to overcome several long-standing challenges in carbon dioxide conversion. By separating the capture and conversion steps, they avoided the problem of oxygen interference that has hampered previous attempts at direct air conversion. The system also achieves higher conversion rates by concentrating the captured CO2 before processing it.
The heart of the conversion process relies on a specially developed hybrid catalyst combining molecular and semiconductor materials. This catalyst efficiently converts the concentrated CO2 stream into syngas while using waste plastic-derived compounds as an additional reactant, potentially addressing two environmental challenges simultaneously.
Unlike previous approaches that required pure CO2 or high temperatures and pressures, this system operates under mild conditions and can process CO2 directly from air. The researchers demonstrated that their device could continuously capture CO2 for about nine hours during simulated nighttime operation, then release and convert it during the day.
The technology shows particular promise for decentralized applications, potentially allowing for fuel production in remote locations or off-grid settings. โIf we made these devices at scale, they could solve two problems at once: removing CO2 from the atmosphere and creating a clean alternative to fossil fuels,โ Kar noted.
The implications extend beyond just fuel production. The syngas produced by the system could serve as a building block for manufacturing various chemicals and pharmaceuticals, offering a pathway to more sustainable industrial processes.
โInstead of continuing to dig up and burn fossil fuels to produce the products we have come to rely on, we can get all the CO2 we need directly from the air and reuse it,โ said Reisner. โWe can build a circular, sustainable economy โ if we have the political will to do it.โ
The research team is currently working on scaling up the technology and developing methods to convert the produced syngas into liquid fuels. With support from Cambridge Enterprise, the universityโs commercialization arm, they aim to begin larger-scale tests in the coming months.
The research, published in Nature Energy, was supported by UK Research and Innovation, the European Research Council, the Royal Academy of Engineering, and the Cambridge Trust.
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