This Solar-Powered Reactor Sucks CO2 From the Air and Turns It Into Fuel

Researchers at the University of Cambridge have built a solar-powered reactor that converts atmospheric carbon dioxide (CO2) into a gas that could one day fuel vehicles, power off-the-grid dwellings, and even produce pharmaceutical products.

The researchers say were inspired by photosynthesis and claim that their technology can be scaled up more easily than earlier solar-powered devices. The team’s research was published today in the journal Nature Energy.

Carbon capture and storage (which is exactly what it sounds like) is a possible means of reducing greenhouse gas emissions. The problem is that most carbon capture technologies are themselves powered by burning fossil fuels—not to mention the fact that the CO2 captured in the process needs to be stored somewhere, such as deep underground. But a new reactor could solve all of that.

“What if instead of pumping the carbon dioxide underground, we made something useful from it?” Sayan Kar, a chemist at the University of Cambridge and first author on the study, said in a university statement. “CO2 is a harmful greenhouse gas, but it can also be turned into useful chemicals without contributing to global warming.”

Kar and his colleagues’ new reactor is completely solar-powered, meaning it requires no cables or batteries. At night, it filters CO2 from the air—similar to how a sponge soaks up water, according to the researchers. During the day, sunlight heats up the collected CO2, which absorbs the Sun’s infrared radiation while a semiconductor powder absorbs the ultraviolet radiation. A mirror on the reactor concentrates the sunlight for greater efficiency in the system.

The absorption initiates a chemical reaction in the reactor that converts the CO2 into synthesis gas, or syngas, a mixture of carbon monoxide (CO) and hydrogen (H2) that is an important ingredient in the production of many fuels and chemicals. The team is currently researching how to convert this solar syngas into liquid fuels that could one day sustainably power vehicles like cars and planes.

“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,” said Kar. “CO2 is seen as a harmful waste product, but it is also an opportunity.”

The researchers claim that a solar reactor of this kind could even be used by individuals (as opposed to powering an entire neighborhood or town) to provide energy for remote locations. Furthermore, because of syngas’ prevalence in the production of chemicals, solar syngas could also lessen the carbon footprint of the chemical sector.

“Instead 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,” said Erwin Reisner, a chemist at the University of Cambridge who led the study. “We can build a circular, sustainable economy—if we have the political will to do it.”

Here’s hoping that we’ll be seeing solar-carbon-capture-reactor-powered cars on the market sooner than we think.