You can try NaBh4 or even natural ascorbic acid (vitamin C)

You can use thermal reduction in order to avoid the use of strong reducing agents

Zinc and Hydrochloric acid. There is a paper in the Journal CARBON that describe this process.

you can use ammonia solution depending upon quantity of GO. It takes quite time but Slow reduction by ammonia solution prevents aggregation of graphene sheets. In addition to that you can use thermal reduction (just heating) as suggested by Vanesa; NaBH4, ascorbic acid, (@Bihag)

I have used hydrazine and ammonia for reduction graphene oxide, you can use NaBH4 after reduction by hydrazine to facilitate the reduction to groups epoxide which not was reduced by hidrazine. See methods above.

Please, I suggest you to read this paper. Aqueous Only Route toward Graphene

from Graphite Oxide Liao et al., ACSNAno 5(2), 1253

There are several methods to reduce GO to graphene. Even you can reduce it with hydroquinone, flash light of a digicam (JACS Comm), or tea (J. Mater Chem.) or sunlight!!. But I think its better not to reduce it hydrogen gas at high temperature, as hydrogen has a strong affinity to carbon, and it may lead to the formation of graphane(hydrogenated graphene). Depending on your requirement you can choose the reducing agent. For references, you may see: arXiv:1207.1995 [cond-mat.mes-hall]

If the time is not an issue, l-ascorbic acid might be a good option. L-AA is a environment friendly reluctant, relative cheap and easy to handle.

Graphene oxide (GrOX) & graphite oxide (GOX) are subjects with long story. Since Hummer method, GOX is originated from graphite oxidation in nitric-sulfuric acid via strong oxidants such as potassium permanganate. Recently preoxidation with persulfates improved oxidation. GOX has been seen as potential candidate for intercalated graphite with Li or other metals for batteries, supercap to name few. Otherwise first applications is in sealing at high pressure - high temp. GrOX derive from GOX as 1 up to few layers depending of method of oxidation. GrOX is seen as precursor for graphene against scotch tape, CVD or other methods less productive but good to redisign nanocomposites or chemo/biosensors. What is GroX-?? an large aromatic carbon structures decorated with functional groups :-OH, -CO, -COO, -COOH ( to name few). Classical chemistry associate this with humic acid ( for example) or similar. To reduce GrOX to Graphene each one find appropriate solution: hydrogen at moderate temp, hydrazine, tetraborohydride ( leaves boron oxide as impurities), ascorbic acid ( partial reductant) quinone, whatever you have in mind. Each one has pros and cons. Flash light in UV or flash heating work well ( you will get domino effect). Light scribe ( laser inscription by local heating) afford you to design small garphene circuits. GrOX by its functional groups makes it versatile to attach other functions with expectations to get an electrical signal ( hard to work). Anyway is good for supercap in combination with semiconducting polymers.

In conclusion your reductant is most appropriate function of your application. Otherwise we can tackle long time. By the way why graphene are so beautiful as support catalyst for fuel cells and all papers finish only with electrochemical characterization and no one gives a fuel cell based on graphene???????

thank you mr.stamatin,i plan to make a nanofluid with high quality nanosheets of graphene,CVD or mechanical cleavage or epitaxial growth are costly and have difficulties for industrial applications so i decided to find a better reduction method(better than reduction with hydrazine) leading to produce high quality , monolayer of graphene im looking for a safe,.imflamabe method

time is not my concern

Thanks mr.lima

what was the quality of obtained geraphene nanosheets?c/o?defects?

Did you find this method better than reduction with hydrazine only?

Thanks mr.saxena and Chin Yong Neo

can you do me a favour and mention the exact link for those refrences?

Recently copper metal nanoparticles are used as a reducing agent in preparation of graphene. Pls see attachment. Authors claim that the method the used is eco-friendly and facile

hydrothermal reaction in a reactor at very high temperature (~300C) and high pressure

Physical methods like microwave, thermal, light.. read this review:

dx.doi.org/10.1016/j.carbon.2011.11.010

The reduction of graphene oxide

http://www.sciencedirect.com/science/article/pii/S0008622311008967

Amir, just add NaOH/KOH to solution of GO, it will give you G.

DOI: 10.1002/adma.200801306

I am agree with christian punckt.yes,NaBH4 is the good reducing agent than hydrazine...

I am agree with christian punckt.yes,NaBH4 is the good reducing agent than hydrazine...

references:Efficient Reduction of Graphite Oxide by Sodium Borohydride and Its Effect on Electrical Conductance

New insights into the structure and reduction of

graphite oxide

New insights into the structure and reduction of

graphite oxide

above article more cited by: 1423

You can try NaBH4 reduction method it is very easy.

Chemical reduction of graphene oxide: a synthetic chemistry viewpoint, this papar can help u so much ....

Article Chua, C. K. & Pumera, M. Chemical reduction of graphene oxid...

Please, check this: Vitamin C Is an Ideal Substitute for Hydrazine in the Reduction of Graphene Oxide Suspensions, DOI: 10.1021/jp100603h. It is the best in terms of safety!

please read this article 

Bull . Mater.  Sci., vol 38, No.3 June 2015, p 739-745

Synthesis of graphene using gamma radiations.

by LEILA SHAHRIRY and ANJALI A ATHAWALE , from university of pune, India

if you  have gamma irradiationn chamber ,  the procedure is simple