Vapor–Liquid Deposition Strategy To Prepare Superhydrophobic and Superoleophilic Graphene Aerogel for Oil–Water Separation

The problems of high temperature and volume shrinkage are frequently encountered in the process of fabricating superhydrophobic graphene aerogels. We present ultralight graphene aerogels with superhydrophobicity and superoleophilicity by a vapor–liquid deposition process. The graphene aerogels are prepared by graphene oxide assembled into monolithic graphene hydrogel in dopamine-mediated aqueous solution at mild temperature and a sealed reaction, then by directional freezing and freeze-drying. Subsequent fluorinated alkyl silane is introduced to produce ultralight graphene aerogel by vapor–liquid deposition treatments; the surface of the aerogel has outstanding superhydrophobicity and superoleophilicity with water and oil contact angles of 160.2° and 0°, respectively. In addition, the resulting graphene aerogels showed super low density, large specific surface area, excellent adsorption capacities, and superior adsorption recyclability. Its adsorption capacity was higher than 109 g/g for the used common oils and organic solvents. Its properties suggest applications in the field of oil adsorption and oil–water separation. The new strategy may open up a new way to design high-performance superhydrophobic 3D graphene monoliths for water treatment.