This solar reactor turns CO₂ into fuel without using fossil energy
The effects of climate change are becoming impossible to ignore, from record-breaking heatwaves to erratic cold spells. Reducing CO₂ emissions has become a global priority. Now, a breakthrough from British scientists could change how we tackle it: a solar-powered reactor that can transform carbon dioxide into liquid fuels like diesel or methanol.
In the race against global warming, carbon capture and storage — or CCS — has long been promoted as a solution to industrial and energy-related emissions.
The process uses several methods — post-combustion, pre-combustion, and oxy-combustion — to extract carbon dioxide from factory and power plant exhaust gases. Once captured, the CO₂ is transported to secure sites and injected deep underground for storage. The U.K. government has even pledged £21.7 billion (about €25.3 billion) to develop this technology.
Still, CCS is energy-hungry and its long-term reliability is widely debated. Transforming CO₂ directly into clean liquid fuels might be a far more effective alternative — and that’s precisely what researchers at the University of Cambridge are working on.
An alternative inspired by nature
Led by Professor Erwin Reisner, the Cambridge team has spent years studying ways to convert waste, water, and CO₂ into usable fuel by mimicking the process of photosynthesis. In a recent statement, Reisner criticized CCS: “Beyond its cost and high energy use, this technology often serves as an excuse to keep burning fossil fuels — the main drivers of global warming.” Storing CO₂ underground, he added, “isn’t circular and doesn’t allow for recycling — it’s basically useless.”
His group’s goal is simple yet revolutionary: use CO₂ not to bury it, but to turn it into a reusable source of energy. Their latest prototype, a solar-powered flow reactor, improves on current conversion methods by separating CO₂ capture and conversion into distinct steps. This design avoids interference from oxygen in the air, boosting both efficiency and conversion rates.
An optimized daily cycle for local fuel production
The Cambridge reactor runs on a two-phase daily cycle. At night, silica and polyamine filters soak up CO₂ from the surrounding air like sponges. During the day, powered by sunlight, the captured gas is converted into syngas — a mixture used to make liquid fuels and a range of industrial chemicals.
In their Nature Energy paper, the researchers describe an advanced hybrid catalyst that blends molecular materials with semiconductors to convert CO₂ more efficiently. Even better, the system can use plastic waste as a reactant, cutting emissions while repurposing trash — a dual benefit for the environment.
This technology could make energy production more sustainable by allowing decentralized fuel generation — even in remote areas. “If produced at scale, these reactors could tackle two crises at once,” said Dr. Sayan Kar, the study’s lead author and a researcher in Cambridge’s Yusuf Hamied Department of Chemistry. “They would lower atmospheric CO₂ while creating a clean alternative to fossil fuels.” He added, “CO₂ is often seen as a harmful waste, but it’s actually a valuable resource.”
A step toward commercialization
The team now aims to refine the process and scale up the technology to turn syngas into liquid fuels. With help from Cambridge Enterprise — the university’s innovation arm — large-scale trials are already being planned.
Their mission is clear: bring the technology to industry and accelerate the energy transition. As Reisner put it, “We already have the tools to build a circular, green economy — all we need now is the political will.”