Hello Lokesh, Graphene oxide can be synthesized from graphite by a few methods, one of which is modified hummer's method. The graphene oxide itself is in the range of 1- 2 nm if it yields appropriately.

The need for reduction is to make the material conducting because the GO shows more resistance due to the functional groups (C–OH, C–O–C, C=O, and O=C–OH groups) attached to it

This reduction can be made either by chemical or thermal. The following links give an idea of them.

https://ars.els-cdn.com/content/image/1-s2.0-S0008622317303858-egi10SH61R018F_lrg.jpg

Article Thermal reduction of graphene oxide: How temperature influences purity

Guruprasad Gorthala Thank you sir for your reply. Which reduction technique is more effective, Chemical based or by thermal reduction?

Dear Lokesh,

1. Chemical reduction: This method is accurate and can be produced the same conductivity multiple times. (More repeatable). But need chemicals to carry out and is difficult compared to thermal reduction.

2. Thermal reduction: This method is simple and doesn't need chemicals for reduction. But difficult to achieve repeatability (same conductivity every time)

As suggested by Guruprasad Gorthala , you can even try to initially reduce the GO by chemical method and further reduction can be by annealing it. if you control the coating volume ,area and the reduction temp, you can somewhat achieve similar conductivity.