Hydrolysis of cellulose by sulfonated magnetic reduced graphene oxide

Reduced graphene oxide functionalized with magnetic Fe 3 O 4 nanoparticles and –PhSO 3 H groups (Fe 3 O 4 -RGO-SO 3 H) was reported for environmentally benign hydrolysis of cellulosic materials, which is an important process in integrated utilization of biomass resource. Except for –PhSO 3 H groups, –COOH and –OH groups derived from graphene oxide (GO) were also expected in the structure of Fe 3 O 4 -RGO-SO 3 H. Fe 3 O 4 -RGO-SO 3 H 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 Fe 3 O 4 -RGO-SO 3 H 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 β-1,4 glycosidic bonds. Furthermore, Fe 3 O 4 -RGO-SO 3 H can also be easily separated from the reaction residue with an extra magnetic force and further used at least five times.