Artificial photosynthesis is emerging as a technology with many applications, including the production of hydrogen, electric power and chemicals. The most promising devices absorb ambient carbon dioxide (CO₂) but only from pressurized tanks under laboratory conditions.

Researchers from the University of Illinois at Chicago have designed an artificial leaf that could operate under Schematic of the artificial leaf. Source: University of Illinois at Chicagoreal-world conditions, capturing CO₂ from air and creating oxygen and synthetic fuels using sunlight. The photosynthesis system, consisting of a light absorber coated with catalysts, is encased in a transparent layer that serves as a water-filled, quaternary ammonium resin-based semi-permeable membrane.

As the water evaporates out under solar irradiation, CO₂ is pulled in and converted to carbon monoxide (CO) by the artificial leaf catalysts. The CO produced can be exploited for synthetic fuel fabrication while the oxygen generated can be collected or released to the environment.

The design is estimated to be up to 10 times more efficient relative to a natural leaf in converting CO₂ to fuel. About a half ton/day of CO could be produced with an array of 360 leaves, each 170 cm long and 20 cm wide, covering a 500 m² area. Such a setup would reduce CO₂ levels within 100 m by 10%.