Fabrication of Robust Graphene Aerogel Microspheres via Macromolecular Skeletal Support and Silicon Doping Toward Highly Efficient Oil Sorption

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The global oil pollution crisis has created an urgent demand for efficient oil-absorbent materials, while graphene aerogel microspheres have emerged as highly promising candidates, owing to the superhydrophobicity, high specific surface area, and enhanced dispersibility in aqueous environments for application. In this study, robust reduced graphene oxide aerogel microspheres (rGO-PAA/PEG AMs) with outstanding oil sorption capacities were fabricated via high-pressure spraying/freeze-drying/high-temperature reduction process employing poly(acrylic acid) (PAA)/polyethylene glycol (PEG) as macromolecular skeletal supports and self-sacrificial templates. During spraying/freeze-drying stage, the electrostatic and hydrogen bonding interactions between PAA/PEG and GO endowed the system with excellent dispersion stability and moderate GO stacking, reducing microsphere breakage. During high-temperature reduction stage, PAA/PEG underwent in situ decomposition, elevating the specific surface area and porosity of the microspheres. Compared with rGO AMs, rGO-PAA/PEG AMs showed a 124.2% improvement in mechanical strength, enhanced sorption capacities for various oils and excellent cyclic sorption stability. Furthermore, through vapor-phase silanization, silicon was bonded to rGO-PAA/PEG AMs via Si–O–C covalent bonds, creating a unique tremella fuciformis-like biomimetic structure. This structure facilitated oil diffusion into the microspheres, resulting in enhanced hydrophobicity and high sorption capacities for various oils (e.g., 369 g/g for pump oil), and thus enabling efficient demulsification and oil–water separation.