Applied Surface Science, Vol.486, 303-311, 2019
Hydrophobic, blocky silica-reduced graphene oxide hybrid sponges as highly efficient and recyclable sorbents
Silica aerogels are prone to be destroyed due to their brittleness and low mechanical properties, which limits their applications. To break the unfavorable situation, we presented a scalable and facile approach to assemble blocky silica-reduced graphene oxide (SiO2-rGO) hybrid sponges by atmospheric pressure drying technique. Briefly, ungelled silica solution from two-step sol-gel of tetraethoxysilane (TEOS), was incorporated into compressible graphene sponge (CGS). Different silicon concentration ratios had great influence on the performance of hybrid sponges. When V-TEOS: V-ethanol was fixed at 1:15, the sample had good flexibility and could absorb 8.5-10.2 times its own mass of solvents, but the adsorption efficiency slightly decreased with the increase of the number of experiments. When V-TEOS: V-ethanol was fixed at 4:7, the SiO2-rGO hybrid sponges exhibited unbroken shape, low volume shrinkage (24%), large specific surface area (803.351 m(2)/g), and high mass retention (83.64%) at 790 degrees C of thermal treatment. Moreover, they could support approximately 146 times their weight without structural damage, and possess excellent hydro-phobicity with 129 +/- 1 degrees of water contact angle. These superior properties enable SiO2-rGO hybrid sponges to exhibit highly efficient absorption of oils and toxic solvents, to be regenerated (10 times) with the full release of adsorbates by heat treatment.