Figure 1. Autonomous oil collection by graphene vessel.

(a) Schematic illustration of oil collection by graphene vessel. Graphene vessel floats on the surface of water due to its hydrophobic surface and buoyancy. Water (blue spheres) is repelled by the vessel. When the vessel gets in contact with the oil layer, it quickly absorbs oil (black spheres) by capillary force and oleophilicity of graphene foam. After the oil is fully absorbed in the foam walls of the vessel, the oil is collected into the vessel by gravity through the entire area of the vessel. (b) Optical images of an experimental graphene vessel collecting crude oil. Front, rear, and bottom sides of the vessel except for the two opposing sides were made of acrylic plate for observation. The vessel suctioned the crude oil floating on the water, and held the liquid body of the collected oil in the vessel.