A hydrothermal-carbonization process for simultaneously production of sugars, graphene quantum dots, and porous carbon from sugarcane bagasse.

A green and facile approach was proposed to simultaneously produce fermentative sugar (FS), graphene quantum dots (GQDs), and hierarchical porous carbon (HPC) from sugarcane bagasse through the hydrothermal-carbonization process. In this work, the maximum yields of FS were 35.77%, 30.54%, 1.23%, 28.52%, and 41.85% for xylose, mannose, glucose, galactose, and arabinose, respectively. The GQDs, with bright blue fluorescence, had an average diameter at 2.26 nm, and exhibited a well-defined spherical shape and graphene structure. The formation mechanism of GQDs was further investigated, and the GQDs mainly derived from the dissolved lignin and polysaccharides. Moreover, the HPC presented a much higher surface area and controllable oxygen content than non-hydrothermal pretreatment porous carbon, whose unique pore structure was mainly resulted from the dissolution of FS. The green and facile approach provides a novel pathway to produce high value-added materials from sugarcane bagasse, developing a foundation for the preparation of better biomass materials.