▎ 摘　　要

Graphene has received great attention because of its exceptional properties and formidable potential in various applications. A practical approach to the production of processable graphene sheets in large quantities at low cost is the key to exploiting most proposed applications. Here we show a dehydration and stabilizer-free method for facile and cost-effective production of water dispersions of graphene nanosheets with concentrations up to 0.05 mg mL(-1) using concentrated sulfuric acid or phosphoric acid as the dehydrating and intercalating reagent. The unique opto-electronic properties of graphene could be chemically engineered without losing the macroscopic structure integrity. The self-assembly properties of as-prepared graphene nanosheets in aqueous solution and at the air/water interface offer great flexibility for a wide range of applications.