Dear Zafer,

You can prepare the dispersión by this way:

http://pubs.acs.org/doi/pdf/10.1021/jp501930a

and then deposit by drop casting in the surface of your surface. Also is posible to modified it by spray deposition.

I did this before, you also can use this way to prepare the dispersion:

http://pubs.acs.org/doi/abs/10.1021/ac402154z

In this docement also presented how to modify electrode by rGO by drop casting.

Thank you so much

Prof. coleman science paper has details about suspension of layered materials

which uses different solutions and surfactant to do so. 

check it out.