Construction Of Bimetallic Active Centers For Selective Reduction Of Furfural Via Catalytic Hydrogenation

To globally reduce the dependence of manufacturing industry on fossil resources and resolve the derived environmental issues,seek to develop new utilization scheme of green renewable resources has received worldwide attention.Selective hydrogenation of furfural（biomass platform molecule）produces furfuryl alcohol,which is considered as a high-value biomass chemical that can be widely used in many core areas of national economy（such as chemical industry,agriculture and forestry,medicine,machinery,and construction）to produce resins,fuels,pesticides,coatings,lubricants,etc.Therefore,it is crucial to develop green heterogeneous catalysts which can efficiently hydrogenates furfural to furfuryl alcohol at mild reaction conditions.Till date heterogeneous Au hydrogenation catalyst has been scarcely reported for this reaction due to the low reactivity of Au for H₂ dissociation.In this work,we showed that Au nanoparticles（loading:0.2 wt.%）with a mean size of about 3 nm supported on Cu doped Al₂O₃ can efficiently hydrogenate furfural to furfuryl alcohol in liquid phase at ambient pressure.The characterization results demonstrated that doping a small of amount Cu（2 mol%）toγ-Al₂O₃ may modify the Lewis acidity-basicity ofγ-Al₂O₃ and simultaneously induce the presence of sufficient Cu⁺species on surface,which facilitated the hydrogen transfer from 2-Pr OH to furfural.Moreover,we observed an enhanced reactivity of Au toward molecular H₂ via cooperation with the Lewis acidic-basic Cu-Al₂O₃ support.Hence,100%yield to furfuryl alcohol with a productivity of 0.98 g _FA h^-1 g^-1_cat.at 120°C and 0.1 MPa H₂ can be obtained on Au/Cu-Al₂O₃ catalyst.The prepared Au/Cu-Al₂O₃ catalyst was found reusable and was effective to the concentrated furfural solution,as well as several typical unsaturated aldehydes.Beside that,we reported a magnetic RuCo bimetallic catalyst that was prepared by H₂ treatment of the RuCo composite precursor from a facile one-pot hydrolysis of Co and Ru salts by Na BH₄solution,which can efficiently hydrogenate furfural to furfuryl alcohol at ambient H₂ pressure.The characterization results demonstrated that the Ru:Co molar ratio and H₂-treatment temperature are important for the structural evolution and the metal interaction in RuCo active sites.In addition,we demonstrated that the cooperative Ru~0-Co~0 bimetallic active sites in strong interaction can significantly promote activity and selectivity of the catalyst due to an enhanced adsorption and activation of furfural and H₂,and simultaneously created a strong magnetism in the RuCo catalyst for simple physical separation.Hence,（350H₂）Ru₃Co₁₀₀ catalyst can totally convert furfural to 100%furfuryl alcohol at 120°C under 0.1 MPa H₂ water using only molecular H₂ as hydrogen source.Moreover,the catalyst showed excellent stability during recycling test and can be easily and completely recovered by magnet from reaction solution.