Nanostructured graphene: Forms, synthesis, properties and applications

This thesis describes the synthesis, properties and applications of the nanostructured graphene with different dimensionalities from 3D foams to, 2D film, and 0D graphene quantum dots (GQDs), and from micron-porous to nanoporous. The applications of the nanostructured graphene include batteries, photoluminescence and cell imaging. Specifically, the thesis comprises the following contents: (1) Nanoporous metallic templates are crucial for the synthesis of nanoporous graphene. A novel method for the synthesis of nanoporous metals was developed and is suitable for industrial production. The growth mechanism, kinetics and microstructures of porous metallic templates were investigated. In addition, the porous metals were synthesized as binder-free current collectors for high-capacity electrodes of lithium-ion batteries. (2) A new solid-state-growth approach is developed for controllable synthesis of nanoporous graphene with interconnected tubular pores and tunable porosities at relatively low temperatures. Nanoporous graphene greatly enhanced the electrochemical performances of high-energy-density Li-S batteries. (3) Large-area graphene film is successfully synthesized at near room temperatures from conversion of amorphous carbon using metallic catalysts. The nucleation, growth process and growth kinetics of graphene were investigated. The results point at several attractive strategies for the facile synthesis of graphene-based carbon films for industrial applications. (4) GQDs were successfully exfoliated from abundant carbon feedstocks such as carbon black in liquid phases with the assistance of ultrasonication. The new approach is eco-friendly and promising for large-scale production. GQDs delivered photoluminescence and light absorption properties, which are firmly associated with their microstructures. The as-synthesized GQDs show good performances as fluorescence nanoprobes for bioimaging