National Natural Science Foundation of China [11174227]; National Basic Research Program of China (973 Program) [2009CB939705]; Ministry of Education of China; Fundamental Research Fund for the Central Universities [2011202020003]; MOE [NCET-10-0643]; NSFC [11104207, 91123009, 10975109]; Hubei Province Natural Science Foundation [2011CDB271]; Natural Science of Jiangsu Grant [BK2011348]; The Grant of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology) ; We report a simple and effective route to convert graphene oxide sheets to good quality graphene sheets using hot pressing. The reduced graphene oxide sheets obtained from graphene oxide by low temperature thermal exfoliation are annealed at 1500 degrees C and 40 MPa uniaxial pressures for 5 min in vacuum. No appreciable oxygen content was observed from X-ray photoelectron spectroscopy and no D peak was detected in the Raman spectrum. The graphene sheets produced had a much higher electron mobility (1000 cm(2) V-1S-1) than other chemically modified graphenes. (c) 2012 Elsevier Ltd. All rights reserved.