Reduced graphene oxide functionalized with magnetic Fe3O4 nanoparticles and -PhSO3H groups (Fe3O4-RGO-SO3H) was reported for environmentally benign hydrolysis of cellulosic materials, which is an important process in integrated utilization of biomass resource. Except for -PhSO3H groups, -COOH and -OH groups derived from graphene oxide (GO) were also expected in the structure of Fe3O4-RGO-SO3H. Fe3O4-RGO-SO3H exhibited outstanding catalytic performance for the hydrolysis of cellulosic materials, due to its crumpling feature with clear layers and the coexistence of -COOH and -OH groups. The unique structure of Fe3O4-RGO-SO3H favors the accessibility of cellulose to the active sites of the material and facilitates the diffusion of the product molecules. -COOH groups on the surface of the material provide a large concentration of acidic functionality for hydrolyzing cellulose, while -OH groups readily adsorb cellulose through forming strong hydrogen bonds between -OH groups and the oxygen atoms in beta-1,4 glycosidic bonds. Furthermore, Fe3O4-RGO-SO3H can also be easily separated from the reaction residue with an extra magnetic force and further used at least five times. (C) 2015 Elsevier B.V. All rights reserved.