In the present work, a green and sustainable route for preparation of hydrochars from sulfuric acid hydrolysis solution of rice husk under low temperature and atmospheric pressure was described. This route was achieved with the catalysis of sulfuric acid. The sphere-like carbon materials with regular size of about 500 nm were obtained at 95 degrees C for 6 h when the acid concentration was 42% and 52%. The morphology of the hydrochars changed with sulfuric acid concentration increased. The surface of the materials contained a large number of functional groups. Furthermore, the localized graphitic nature of the materials was proved by X-ray diffraction pattern. High surface area porous carbons could be prepared from the hydrochars after activation, and they exhibited good electrochemical performance. (c) 2010 Elsevier Ltd. All rights reserved.