Few layer graphene synthesis on transition metal ferrite catalysts

Development of cheap, green and up scalable production methods for graphene is one of the most challenging problems in its manufacture on an industrial scale. We report here a large scale substrate-free fluidized bed catalytic chemical vapour deposition (FB-CCVD) process for few layer graphene (FLG) powder production that uses a crystalline oxide catalyst of the general formula AxB3−xO4, wherein the FLG layer thickness and domain sizes can be varied. A and B can be chosen from a list of transition elements including Co, Fe, Ni, Mn, Cu and Zn. The best results in terms of activity and selectivity are obtained for the CoxFe3−xO4 system. We also investigated the reaction mechanism using in situ EXAFS and Raman spectroscopy, and electron tomography. Since FB-CCVD processes are already used for industrial scale production of carbon nanotubes, this process should enable the large scale production of free standing FLG in the near future.