Comparative Study on Graphene Aerogels Prepared by Different Methods and Their Adsorption for Organic Solvents

The atmospheric drying and freezing drying were utilized to prepare graphene aerogels (GAs), and the effect of the different drying methods and the key parameters on their structures and properties were comparatively investigated. Three kinds of GAs were synthesized using different reduction and drying ways. GA1 was prepared by subtly regulating the structure of the hydrogel and using an atmospheric drying, while GA2 and GA3 were prepared using a common reduction and freezing drying method. The results shows that GA1 possesses a uniform pore structure constituted by lamellar interconnected graphene oxide (GO) sheets with little of stacking texture, and it is super elastic and can restore to its original shape even after 90% strain. GA1 also has a high adsorption capacity ranging from 90.47-167.24 times of its own mass and a rapid adsorption efficiency toward organic solvents and in addition it possess excellent recyclability. The comparative study indicated that GA1 far surpasses GA2 and GA3 in performance and structure. The study on the formation mechanisms revealed that the subtly regulated structure of the hydrogel is of key importance to the atmospheric drying, and the capillary force up on this drying can be utilized to adjust its pore structure. It is the firstly attempted to investigate the roles of reduction and drying methods upon preparing GAs, and the results will be of great importance to guide the synthesis, design, structure optimization and performance improvement of GAs.