Photolytic Breakdown of Fullerene C₆₀ Cages in an Aqueous Suspension

Fullerene C₆₀, a class of carbon nanomaterials, is widely used and is likely to reach the environment. The degradation and transformation of C₆₀ aqueous suspensions exposed to simulated sunlight were studied. C₆₀ aqueous suspensions prepared by stirring pristine C₆₀ in water under sunlight exposure undergo breakdown with formation of a mixture of compounds with unknown chemical structure. The mass and infrared spectrometric analysis of the breakdown products shows the presence of broken C₆₀ cages, as well as of oxygen and hydrogen atoms in their structure. The presence of oxygen in the breakdown products indicates a possible interaction of C₆₀ molecule with oxygen from the air as well as with water. Interaction with water could also explain the presence of H atoms in the breakdown products. This demonstrates that fullerenes C₆₀ are not stable in the environment and that the breakdown products should be considered when evaluating the environmental impact of fullerenes C₆₀.