Highly Efficient Metal/Zeolite Catalysts For Hydrodeoxygenation Of Biomass Platform Molecules

Biomass and bioenergy reserves are abundant.Through the design and synthesis of metal/zeolite catalytic materials,hydrodeoxygenation of biomass platform molecules is carried out to prepare valuable chemicals and biofuels,which provides a feasible way to solve energy crisis and environmental problems.Aiming at the catalytic hydrodeoxygenation of biomass platform molecules,from the point of view for the design of metal/zeolite catalytic materials,this thesis mainly includes two aspects of work:（1）the design and preparation of Cu/Si-Beta-HT catalytic materials with abundant Cu⁺and Cu⁰species for glycerol hydrohydrolysis to 1,2-propylene glycol;（2）Pd/ETS-10catalytic material with abundant Pd-TiO_x interface and oxygen vacancy was prepared for vanillin hydrodeoxygenation to 5-methyl guaiacol.Catalytic conversion of glycerol to 1,2-propanediol is an important issue for sustainable production of fine chemicals and biodiesel.In chapter 3 of this thesis,it is developed a pure siliceous Beta zeolite supported copper species via hydrothermal treatment（Cu/Si-Beta-HT）for the efficient hydrogenolysis of glycerol to 1,2-propanediol,achieving 96.0%glycerol conversion and more than 99.9%selectivity to 1,2-propanediol after reaction at 240℃ for 3 h.TEM images and N₂O titration experiments confirmed the high dispersion of Cu nanoparticles in the catalyst;pyridine-adsorption FT-IR spectra and NH₃-TPD profiles suggest the presence of copper cations as Lewis acidic sites in the catalyst.These active sites catalyze the dehydration of glycerol to acetol and the hydrogenation of acetol to 1,2-propanediol,respectively.In situ FT-IR spectra and kinetic studies suggest that the dehydration rate is slower than the hydrogenation rate,and the dehydration is a key step for the hydrogenolysis of glycerol to 1,2-propanediol.The development of efficient catalysts for hydrodeoxygenation of vanillin to 5-methylguaiacol is highly desirable.In chapter 4 of this thesis,Pd-TiO_xinterfaces was constructed by loading Pd nanoparticles on ETS-10 zeolite crystals.These interfaces in the Pd/ETS-10 sample are quite efficient for the cleavage of C=O bonds in the hydrodeoxygenation of vanillin,exhibiting>99.9%vanillin conversion and 95.2%5-methylguaiacol yield at 120℃.Characterizations and kinetic studies have confirmed the successful construction of unique Pd-TiO_x interfaces,which activates the C-O bond of the intermediates during reaction.This work might be helpful for the preparation of efficient catalysts for the hydrodeoxygenation of biomass-derived materials in the future.