Fabrication of a mechanically robust carbon nanofiber foam

Abstract

In this thesis, the constrained formation of fibrous nanostructures process was scaled up to fabricate mechanically robust, homogenous foam samples. Scaling up this process required the design of a stainless steel mold capable of maintaining conditions supportive of the carbon nanofiber foam growth such as gas flows, constrained growth area, stable at the temperature and time employed. The gas flow distribution during the growth process was achieved using stainless steel deflectors capable of consistently directing adequate amounts of hydrocarbon to all chamber regions. ANSYS CFX models were used to simulate the gas flows with and without deflectors. Analysis of the experimental variables impact on the foam generation showed that the gas flows and their temperature had a greater influence in the foam robustness than reaction times. Control over the growth variables successfully created an interwoven carbon nanofiber foam material of larger dimensions than previous efforts. The carbon mats microstructures were studied using Scanning Electron Microscopy and their surface area determined by the Brunauer-Emmett-Teller method. The catalyst employed during fabrication was recovered using a leaching method that dissolved the palladium without damaging the carbon foam. The recovery experiment validated the technique as a viable way to reduce manufacturing costs in this process.