Preparation And Catalytic Performance Of Palladium Catalyst Supported On Amino Modified Graphene Oxide For Catalyzing Suzuki Coupling Reaction

In this paper,the palladium catalysts supported on amino modified graphene oxide?GO@PPD-Pd?with layered structure were prepared by self-assembly method and its structure and composition were characterized.Their catalytic performance and mechanism for Suzuki coupling reaction were investigated.The results were as follows:1.The palladium catalysts supported on amino modified graphene oxide?GO@PPD-Pd?with layered structure were prepared and characterized by X-ray diffraction spectroscopy?XRD?,Fourier transform infrared spectroscopy?FT-IR?,Raman spectra?Raman?,X-ray photoelectron spectroscopy?XPS?,Scanning electron microscopy?SEM?,Transmission electron microscopy?TEM?,Transmission electron microscopy-energy dispersive X-ray diffraction?TEM-EDX?,BET specific surface area test?BET?,Electrochemical impedance spectra?EIS?,Thermogravimetric analysis?TGA?,and Inductively coupled plasma-atomic emission spectroscopy?ICP-AES?.2.The catalytic activity,substrate applicability and cycling performance of the catalysts?GO@PPD-Pd?were studied using Suzuki coupling reaction as template.The results showed that the catalysts had excellent catalytic activity and better stability under optimized condition?Et OH/H₂O?V/V=1:1?,K₂CO₃,60?for 20min?,TOF value was as high as 60705 h^-1 and its catalytic activity was not significantly loss after 6 recycles;The catalysts had good substrate applicability for aryl iodides and aryl bromides.The deactivation mechanism was studied by SEM,TEM,EIS,Raman,XRD,and ICP-AES.The results showed that the aggregation and loss of metal active centers during the catalytic process were the key factors for the decrease of catalyst activity.The effects of the Pd content,supports and ligands on their catalytic properties were also investigated.3.Heterogeneous catalysis mechanism was detailed investigated by kinetic and thermal filtration experiments,catalyst poisoning experiments,XPS and React IR.The results were shown as:Heterogeneous catalytic process at the interface for the Suzuki coupling reaction could be proved,in which the real active center was Pd?0?.The oxidation addition reaction during catalytic process could be effectively promoted due to the enhanced negative of active Pd by electron transferring from ligand and carrier.