In a remarkable stride towards sustainable energy, researchers at the University of Cambridge have showcased a method to capture carbon dioxide from industrial sources or directly from the atmosphere and convert it into eco-friendly fuels using solar energy.
The scientists devised a solar-driven reactor capable of converting captured CO2 and plastic waste into valuable chemical products and sustainable fuels. In tests, CO2 was converted into syngas, a key building block for sustainable liquid fuels, and plastic bottles were converted into glycolic acid, which is widely used in the cosmetics industry.
Unlike earlier tests of their solar fuels technology however, the team took CO2 from real-world sources – such as industrial exhaust or the air itself. The researchers were able to capture and concentrate the CO2 and convert it into sustainable fuel.
Although improvements are needed before this technology can be used at an industrial scale, the results, reported in the journal Joule, represent another important step toward the production of clean fuels to power the economy, without the need for environmentally destructive oil and gas extraction.
For years, Professor Erwin Reisner's research group, housed within the Yusuf Hamied Department of Chemistry, has been designing net-zero carbon fuels inspired by photosynthesis. This intricate process, akin to how plants convert sunlight into nourishment, involves artificial leaves that utilize solar power to transmute CO2 and water into fuels. While their earlier solar-driven tests utilized concentrated CO2 from cylinders, the practicality of this technology hinges on its ability to capture CO2 from industries or directly from the air. However, isolating highly diluted CO2 from the mix of molecules present in the air is a formidable technical hurdle.
Ingeniously, the researchers adapted their solar-driven system to operate with flue gas or directly from the atmosphere. By channeling air through the setup containing an alkaline solution, CO2 is selectively trapped, while harmless nitrogen and oxygen gases are released. This process effectively concentrates CO2 from air in solution, streamlining its manipulation.
By bubbling air through the system containing an alkaline solution, the CO2 selectively gets trapped, and the other gases present in air, such as nitrogen and oxygen, harmlessly bubble out. This bubbling process allows the researchers to concentrate the CO2 from air in solution, making it easier to work with.
Their comprehensive setup involves a photocathode and an anode, separated into two compartments. One side houses the captured CO2 solution, transformed into syngas, a basic fuel, while on the other, plastics are converted into valuable chemicals solely powered by sunlight.
Presently, the scientists are actively developing an efficient and practical bench-top demonstrator to highlight the advantages of combining direct air capture with CO2 utilization, paving the way for a carbon-neutral future.
Sources: University of Cambridge.
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