Unlike most carbon capture technologies, the reactor developed by the Cambridge researchers does not require fossil-fuel-based power, or the transport and storage of CO₂, but instead converts atmospheric CO₂ into an industrially-useful substance using sunlight. Results of the study, led by Professor Erwin Reisner, have been reported in the journal Nature Energy.

The focus of Reisner’s research group is the development of devices that convert waste, water and air into practical fuels and chemicals. These devices take their inspiration from photosynthesis, the process by which plants convert sunlight into food.  

The team’s newest system takes CO₂ directly from the air and converts it into syngas. The researchers say their approach is much easier to scale up than earlier solar-powered devices.

The device, a solar-powered flow reactor, uses specialised filters to grab CO₂ from the air at night, in the way that a sponge soaks up water. When the sun comes out, the sunlight heats up the captured CO₂, absorbing infrared radiation. Inside the device, a semiconductor powder absorbs the ultraviolet radiation to start a chemical reaction that converts the captured CO₂ into solar syngas. A mirror on the reactor concentrates the sunlight, making the process more efficient.

The researchers are currently working on converting the solar syngas into liquid fuels, which could be used to power cars, planes and more – without adding more CO₂ to the atmosphere. ‘If 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,’ says first author Dr Sayan Kar. ‘CO₂ is seen as a harmful waste product, but it is also an opportunity.’

The researchers say that net-zero production of syngas is particularly promising for the chemical and pharmaceutical sector, where it can be used for many common products. They are building a larger scale version of the reactor and hope to begin tests in the spring.

Turning captured CO₂ into valuable materials: Progress in research worldwide

Other researchers are also making strides in transforming captured CO₂ into valuable materials.

A team at Atlanta’s Georgia Tech University, in collaboration with the Korea Advanced Institute of Science and Technology, has developed a new electrochemical reactor that can be integrated into existing direct air capture (DAC) systems. Their approach eliminates energy-intensive steps in traditional DAC methods. Instead, they say, it uses a nickel-based catalyst and a bipolar membrane electrode assembly to efficiently convert captured CO₂ into carbon monoxide gas – a key raw material for producing plastics, chemicals and fuels.  

Meanwhile, researchers at Rice University in Texas have introduced an electrochemical reactor that optimises carbon capture while simultaneously generating hydrogen. Unlike conventional heat-driven DAC techniques that rely on amine-based compounds or sodium hydroxide – both costly and environmentally-challenging – the Rice reactor uses electricity to capture CO₂ at room temperature without unwanted byproducts.