Metal-free bifunctional graphene oxide-based carbocatalysts toward reforming biomass from glucose to 5-hydroxymethylfurfural

Graphene oxide (GO) and its derivatives are promising metal-free heterogeneous catalysts due to their high surface area and rich chemical properties. We developed a bifunctional boron-doped sulfonated graphene oxide (BS-GO) and demonstrated its excellent catalytic conversion of glucose to 5-hydroxymethylfurfural (HMF) in a one-pot reaction. BS-GO afforded a high HMF yield of 36.0% from glucose without the use of additives or strong acids. Furthermore, the origin of the catalytic active sites of BS-GO was investigated, unveiling the unique bifunctional catalytic mechanism; it was revealed that two disjunct moieties, boronic acid and phenylsulfonic acid, in a single nanosheet of BS-GO catalyst have a bifunctional effect resulting in excellent catalytic production of HMF. This study suggests the potential of BS-GO as a green and sustainable carbocatalyst for reforming biomass to produce value-added chemicals. We anticipate that the unique structural design presented in this study will provide a guide to afford viable carbocatalysts for diverse organic reactions.