A Cyclic Catalyst Pretreatment in CO2 for High Yield Production of Carbon Nanofibers with Narrow Diameter Distribution

This paper presents a cyclic catalyst pretreat- ment process to improve the CNF yield with narrow size distribution by sequentially feeding the CVD reactor with CH4/CO2 mixtures (carbon deposition) and CO2 (carbon removal) prior to the actual growth process. A mechanism based on a break-up of large Ni particles tentatively explains the beneficial effect of the cyclic carbon deposi- tion/removal CVD procedure.