CVD Growth of Porous Graphene Foam in Film Form

Abstract

© 2020 Elsevier Inc. Porous Cu/Ni foils were made by electroplating Ni on Cu foils and used as templates for chemical vapor deposition growth of porous graphene foam. The walls in the graphene foam were found to be two to five graphene layers thick, interconnected to form a low-density porous network with a wide distribution of pore sizes and a high electrical conductivity. A comprehensive comparison with previously studied materials for electromagnetic interference (EMI) shielding showed that this graphene foam is among the best EMI shielding materials; its specific EMI shielding effectiveness (>720 dB cm3 g−1) and absolute effectiveness (>45,000 dB cm2 g−1) are superior to those of most other materials. This graphene foam has a large absorption capacity for various organic solvents and oils and adsorbs them within seconds. The synthesis strategy should provide a general approach for generating other 3D porous structures, including those based on a variety of known 2D materials, for various applications. Graphene foam can be flexible and have large specific surface area and low density. Foams composed of reduced graphene oxide sheets typically have “modest” electrical conductivity, and foams templated by chemical vapor deposition (CVD) growth on Ni foam have a very large pore size of about 500 μm. We electrochemically generated porous Ni films on Cu foil and, after annealing the resulting porous Cu/Ni films, enabled CVD growth of porous graphene foams in film form that have a very wide distribution of pore sizes. These high-porosity graphene foams have high electrical conductivity and provide excellent electromagnetic interference (EMI) shielding and fast adsorption of organic solvents. Our approach appears to be scalable for mass production of foams with few-layer graphene comprising walls that could find a variety of uses, such as support structure for catalysts, in electrical energy storage, and for EMI shielding. A new approach to make low-density and high-porosity graphene foams in film form is presented. The foam thickness can be readily tuned. The graphene foam has excellent electrical conductivity and is hydrophobic. It provides superior EMI shielding and rapid absorption of organic solvents. CVD of few-layer graphene on porous Cu/Ni generated by electrodeposition of Ni on Cu followed by heat treatment and dissolution of Cu/Ni yields the graphene foam by a method that appears to be scalable to mass production