Faculty Sponsor's Department:
Graphene foams have started to generate interest due to their unique structure and corresponding high surface area, but limited research has gone into further increasing that surface area or into forming metal-graphene porous composites. We developed a CVD method (patent pending) for synthesizing Cu-graphene foams with significantly smaller pores (up to ~95% reduction) than those of published foams, allowing for higher graphene loading. This was done by heating Cu powders until they fused into a porous scaffold and then introducing as the precursor for graphene growth. Although mechanical testing was not completed in time for the project's completion, it is hoped that the higher graphene loading will result in a material stronger than pure Cu. Two tangential lines of research were also investigated: (1) annealing the foams into solid composites, and (2) etching the Cu to form free-standing graphene foams (GFs). Additional annealing reduced the foam's porosity by 3, but graphene was etched in the process. A change of CVD parameters allowed us to maintain graphene coverage, but doing so prevented the Cu from softening into a less-porous block. Avoiding this tradeoff requires further experimentation. As for the GFs, ammonium persulfate effectively etched the Cu while retaining the graphene coating. Once removed from solution, however, the GFs were prone to collapse, a problem that was not resolved. This was an introductory investigation that provided an overview of the problems with and potential of Cu-graphene foam composites, data on which future research and applications can build.