First thing - I'm not a graphene expert :-) and I don't know the specific literature around ferrocene/bagasse

However, I do know stuff about CNTs. Ferrocene is often used as a precursor molecule to generate the iron-based catalyst nanoparticles which are used to grow CNTs - so you're correct in identifying its role.

Ferrocene begins to thermally decompose at ~450C, breaking down to give iron atoms and hydrocarbon molecular fragments

I Imagine that the challenge will be getting the ferrocene to form a suitable planar catalytic surface. - as it decomposes, the iron atoms generally coalesce to form nanoparticles (this is the process that CNT growth relies on)

I guess that one approach might be to prepare a substrate with a single layer of ferrocene molecules on it, to try and produce a uniform Fe layer for your GO growth. However - you might find that Ostwald ripening processes cause coalescence of the atoms and nanoparticle growth.

Don't be too surprised if you find some CNTs in your product - good luck!

I totally agree with Dr. Fiona Smail explanation.

However, graphene oxide normally prepared and purified using the Hummers method. If you add a ferrocene during the pyrolysis of sugarcane bagasse using CVD, you may obtain CNTs.

Ferrocene can exfoliate the graphene sheets, resulte in single layer graphene sheet

Take a look at this article: DOI: 10.1039/C0NR00024H