A Fully Light-Driven Approach to Separate Carbon Dioxide from Emission Streams

Carbon capture from industrial point sources is an essential component of the global effort to mitigate climate risks. However, traditional approaches require significant energy input—often provided, counterproductively, by fossil fuel combustion. Using sunlight directly as the energy source would significantly improve the energy efficiency of carbon capture processes. Herein, we report the first fully visible light-driven CO2 separation system, in which carbon capture is achieved via the photoenolization/cycloaddition reaction of inexpensive 2-methylbenzophenone with CO2, and CO2 release is realized through an intramolecular photodecarboxylation reaction. This system operates isothermally, works with natural sunlight, and facilitates CO2 removal from natural gas flue emissions, providing a blueprint for other non-thermal chemical separations.