Your GO might not be fully reduced bcause completely rGO should not be soluble in water. Anyway, whatever the state it is in, you can simply freez dry the water suspension to get powder. hope it helps.

Hi You are getting soluble rGO because of incomplete reduction as a result the oxygen functional groups present in your rGO making it soluble. So you increase the concentration of hydrazine or just change the reducing agent. If you will use strong reducing agent like sodium borohydride it will give you graphene oxide powder. Otherwise if you need graphene oxide powder in the same condition what you have adopted then follow the suggestion as suggested by Ghulam

Thanks all for your responses

But can any one of you tell me the suitable amount of hydrazine for GO 0.5mg\ml is required, we have Hydrazine hydrate (85%) and (62%)

You can use around 10 wt percent against the suspension of GO that you have

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