Preparation of Graphene-MOFs Composite Aerogels

The self-assembly between graphene oxide nanosheets and metal organic frameworks was synthesized by using silk protein as cross-linker and investigated as a method to form three-dimensional porous graphene and MOFs objects with high surface areas and low densities. After freeze drying or supercritical drying of the assembled composite hydrogels, ultralight graphene-MOFs composite network aerogels with high surface areas, hierarchical and nacre-like pore structures, good electrical conductivity, and well-defined bulk shape were obtained. By adjusting the concentration of graphene oxide in the precursor mixture and using different kinds of drying method, aerogels with a density as low as 7.55 mg/cm³ or a surface area as high as 523.5m²/g could be prepared. The absorption performance was evaluated for the aerogel with the lowest density. Graphene aerogel can act as a matrix for immobilization and assembly of MOFs, which could efficiently minimize the potential release of MOFs into the environment. Due to the high porosity and hierarchical pore structure, the aerogel displayed fast absorption rates for malodor gasses as well as high absorption efficiencies. Active catalysts for oxidative treatment of VOCs, NH₃ and H₂S can be dispersed on the new aerogel materials. The graphene-MOFs aerogels are intrinsic bactericides and capable of reducing the viability of airborne bacteria.