Light turns carbon dioxide and methane into useful chemicals

Carbon dioxide and methane, the two most notorious greenhouse gases, are also notoriously inert. Researchers have been trying to convert them to fuels or other valuable chemicals, but the reactions typically require expensive catalysts and a lot of energy. Not anymore. A team in China has directly converted CO2 and methane to fuel precursors using only light (Nat. Photonics 2025, DOI: 10.1038/s41566-025-01800-3).The method converts just 1.5% of the gases, but it “holds promise for utilizing carbon dioxide and methane emissions to produce fuels beyond petroleum,” says Buxing Han, a physical chemist at the Institute of Chemistry, Chinese Academy of Sciences. It’s also a promising route to making fuels and chemicals in space, where the high-energy ultraviolet (UV) radiation needed for the reaction is readily available.The conventional way to break the strong carbon-oxygen bonds in CO2 is to react the gas with hydrogen at high temperatures, but researchers are also pursuing electrochemical routes to convert CO2. Precious metal–based catalysts are key for speeding up the reactions. To reduce cost, some teams are combining solar cells with cheaper catalysts in order to convert CO2 to fuels using sunlight.Han and colleagues found that UV light at a wavelength of 185 nm has enough energy to break the bonds in CO2 and methane and produce carbon monoxide, hydrogen, and ethane (C2H6). Ethane and syngas, which is a mixture of CO and H2, are building blocks for several fuels and compounds.The researchers first shone light from a high-energy UV lamp on the gas mixture in