Design,Preparation And Catalytic Performance Research Of Highly Active Single Atom Catalysts Confined With Stable Carbon Materials

5-Hydroxymethylfurfural（HMF）is a biomass-derived platform compound.Its aerobic oxidation in the liquid phase to 2,5-furandicarboxylic acid（FDCA）is a multi-step and tandem oxidation process.As a new frontier of heterogeneous catalysts,single atom catalysts（SAC）and single atom alloy（SAA）catalysts have been extensively studied due to their maximum metal atom utilization,high catalytic activity and product selectivity.Applying it into the development of HMF oxidation catalyst can improve production efficiency and reduce costs.Herein,we prepared Pt SAC and Pt SAA catalysts,and compared their catalytic performance in the aerobic oxidation of HMF.Based on commercial Pt/C,the FDCA yield of Pt SAC is much lower,but the FDCA yield of Pt SAA is very high.Combined with DFT analysis,the central negative charged Pt atom in Pt SAA promotes the adsorption of key intermediates,meanwhile,the Co atom close to the Pt atom constitutes the optimal O₂ adsorption/activation site.But Pt SAC has almost lost the oxygen adsorption and activation,as well as the key intermediate adsorption.Taking Au and Pd as research objects,Au and Pd double SAC and Au-Pd alloy catalysts were prepared and their activity in the oxidation of HMF was compared.As a result,it was found that the catalytic activity and selectivity of the Au-Pd alloy catalyst were excellent,but the yield of FDCA of the containing Au,Pd catalyst and the double SAC was very low.Through a series of control experiments and structural characterization data analysis,when an alloy bond is formed between Au and Pd,electrons are transferred from Pd with low electronegativity to Au with high electronegativity,resulting in a positively charged Pd atom and a central band.The negatively charged Au atoms act synergistically to show the desired activity and selectivity in HMF oxidation.For a containing Au and/or Pd,there is no interaction between Au and Pd,which is the reason for the lower catalytic activity.Graphene oxide（GO）synthesized by the improved Hummers method,used in the oxidation of furfural（FAL）to succinic acid（SA）with H₂O₂ as the oxidant.Various characterization data and control experiments show that the efficiency of GO is higher than that of conventional catalysts,which is attributed to its unique planar layered structure and the aromatic ring and edge-modified-SO₃H group in GO synergistically act in FAL oxidation.