Photocatalytic synthesis of 2,5-diformylfuran from 5-hydroxymethyfurfural or fructose over bimetallic Au-Ru nanoparticles supported on reduced graphene oxides

[Display omitted] •rGO supported bimetallic Au-Ru catalysts were synthesized and characterized.•Synergistic effect of Au and Ru on rGO increases the formation of DFF.•High DFF yield of 91% can be reached under visible light irradiation.•Superoxide radicals are mainly responsible for the oxidation of HMF to DFF. The photocatalytic conversion of biomass to renewable fuels and chemicals is significant for the sustainable development of energy resources. Herein we report that bimetallic Au-Ru nanoparticles supported on reduced graphene oxides (rGO) exhibit excellent photocatalytic performances for the synthesis of 2,5-diformylfuran (DFF) from partial oxidation of 5-hydroxymethyfurfural (HMF) or one-pot conversion of fructose in the absence of any bases, and the yield of DFF can reach as high as 91% and 86%, respectively. Comparing with rGO-supported monometallic Au or Ru catalysts, the Au-Ru/rGO catalyst shows higher photocatalytic activity due to the transfer of photo-excited electrons from Ru to Au nanoparticles through the conductive graphene support. Since the Au-Ru/rGO catalyst can utilize abundant solar energy, avoid the usage of bases and demonstrate high selectivity and good reusability, the present work provides a green, economical and efficient synthetic route for DFF production.