Preparation Of Modified Mesoporous Material SBA-15 Supported Platinum-based Catalyst And Its Application In Depolymerization Of Lignin

Lignin is the only green renewable resource in nature that can provide benzene rings.With the development and utilization of lignin resuorces,lignin has been becoming an alternative resuorce for human,which can greatly relieve the energy crisis.The depolymerization of lignin into aromatic monomer compounds and further processing into high value-added chemicals or high-quality biofuel has become one of the research hotspots.In this paper,a bifunctional catalyst 4%Pt/Al-SBA-15?10?was prepared with mesoporous molecular sieve SBA-15 doped by aluminum and loaded by platinum.Furthermore the application of this method in the depolymerization of lignin was studied,which provides the theoretical basis and application way for the efficient depolymerization of lignin.In this paper,the influence of doping content of aluminum,calcination reduction temperature and load amount of platinum was explored and the catalyst preparation process and parameters were optimized.Al-NMR and BET,XRD,SEM,TEM,and XPS were used to characterize and analyze the microstructure of the catalyst.The prepared bifunctional catalyst4%Pt/Al-SBA-15?10?with stable acid active center and metal active center has a regular hexagonal mesoporous channel structure,a large specific surface area?470.59 m2/g?,a large pore size?6.24 nm?and large pore volume?0.73 cm3/g?.Because aluminum doping introduces abundant defect sites into the carrier,these defect sites help anchor Due to the introduction of aluminum doping into the carrier,these defects help to anchor the platinum and provide electrons for the platinum,so that the platinum can be reduced more thoroughly.The average particle size of 0 valence platinum is 3.5 nm,which is evenly distributed on the carrier.The optimal condition of the hydrogenolysis of lignin with 4%Pt/Al-SBA-15?10?as catalyst were determined through single-factor experiments,and the distribution of polymer products was analyzed by GC-MS,GPC and other characterization methods.The yield of aromatic monomer and bio oil were 28.32wt%and 85.29wt%respectively in the hydrogenolysis reaction of 0.3g organic solvent lignin with 0.09g 4%Pt/Al-SBA-15?10?as a bifunctional catalyst,and the reaction temperature is controlled at 280?,the reaction time is2 h,the reaction atmosphere is 1 MPa H₂.It was found that the acid active center and metal active center on the bifunctional catalyst 4%Pt/Al-SBA-15?10?could synergistically catalyze the cleavage of aromatic ether bonds,and the regular mesoporous channels could inhibit the product regrouping.Moreover,the acid active center can cut the alcohol hydroxyl group on the side chain of the benzene ring,and the metal active center can promote the hydrogenation of the unsaturated functional group of the side chain of the benzene ring to a saturated state,which is conducive to obtaining high-quality aromatic monomer products.