Recycling of atmospheric CO2 will play a big factor in achieving a net carbon zero future. To demonstrate the same, University of Cambridge researchers developed a solar-powered reactor that converts CO2 captured from industrial waste or even air into sustainable fuel. The reactor uses only sunlight to convert the CO2 into CO + H2, a precursor of industrial liquid fuel production.

At the same time, the team also wanted to integrate the recycling of waste plastics to protect the environment from irreversible damages. The reactor also concurrently upcycled plastic waste to a commodity chemical glycolic acid.

In tests conducted by the team, 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, as per the press release on EurekAlert. 

The reactor is a positive step towards an economy which doesn’t rely on environmentally destructive oil and gas extraction. The overall system operates under simulated sunlight in a two-compartment PEC setup, without the need of any externally applied voltage, said the researchers in their study.

Converting plastic and CO2 into something truly useful

The research group has been working under Professor Erwin Reisner for several years now. The team has been focused on developing sustainable and net-zero carbon fuels based on photosynthesis, using artificial leaves. These artificial leaves convert CO2 and water into fuels using just the power of the sun, explained the researchers in the press release. 

The team’s solar-driven projects till date have been using pure and concentrated CO2 from cylinders. However, the team believes that in order for the process to be sustainable, the CO2 needs to be captured directly from the air or industrial processes. Making this technology selective enough to convert highly diluted CO2 is a huge technical challenge, the researchers noted.

“The plastic component is an important trick to this system,” said first author of the study, Dr Motiar Rahaman. “Capturing and using CO2 from the air makes the chemistry more difficult. But, if we add plastic waste to the system, the plastic donates electrons to the CO2. The plastic breaks down to glycolic acid, which is widely used in the cosmetics industry, and the CO2 is converted into syngas, which is a simple fuel.

“The fact that we can effectively take CO2 from air and make something useful from it is special. It’s satisfying to see that we can actually do it using only sunlight.”