Enhanced Hydrolysis of Cellulose by Highly Dispersed Sulfonated Graphene Oxide

Two-dimensional materials are promising for use as solid acids in cellulose hydrolysis. However, they suffer from a severe problem of restacking, which leads to poor solid-solid contact and decreased catalytic efficiency. Herein, highly dispersed sulfonated graphene oxide (GO-SO3H) nanosheets were prepared and used as solid acids to hydrolyze cellulose. The highly dispersed GO-SO3H was obtained by adding N,N-dimethylacetamide (DMAc). The DMAc improved the dispersibility of the GO-SO3H nanosheets by increasing the zeta potential. The GO-SO3H dispersion had the best dispersibility when the water/DMAc volume ratio was 1:10. The good dispersion of the catalysts increased the accessibility of acid sites to the beta-1,4-glycosidic bonds in the cellulose, which led to a catalytic performance for hydrolyzing cellulose that was superior to that of any other system. When converting cellulose, the total reducing sugars and glucose yields were 78.3% and 69.7%, respectively, which were obtained within 8 h at 130 degrees C.