| In this paper,aryl triimine palladium-copper bimetallic and biimine palladium-iron-ruthenium trimetallic catalytic molecular monolayer anchored on graphene oxide(GO@H-Fe95.7Pd4.26Ru0.01 and GO@T-PdiCu99)were designed and fabricated by self-assembly method.The catalytic performance,stability and catalytic mechanism of the two catalysts were investigated by using Suzuki coupling reaction as a template.The research contents and results are as follows:1.Graphene oxide supported aromatic triimine palladium-copper bimetallic and bisimine palladium-iron-ruthenium catalytic molecular films(GO@H-Fe95.7Pd4.26Ru0.01 and GO@T-PdiCu99)were prepared and their structure and morphology were characterized by X-ray powder diffraction(XRD),Raman spectroscopy(Raman),Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),Scanning electron microscopy(SEM),transmission electron microscopy(TEM),Inductively coupled plasma-atomic emission spectroscopy(ICP-AES),Electrochemical impedance spectra(EIS),and Atomic force microscopy(AFM).2.The catalytic activity,substrate adaptability and stability of the catalysts(GO@H-Fe9s.7Pd4.26Ru0.01 and GO@T-PdiCu99)were studied by using Suzuki coupling reaction as template.The results showed that GO@H-Fe95.7Pd4.26Ru0.01 and GO@T-Pd1Cu99 exhibited high catalytic activity for iodo aromatics and brominated aromatics and could be recycled for 10 times and 6 times,respectively.3.Heterogeneous catalytic mechanism was detailed investigated by kinetic and thermal filtration experiments,catalyst poisoning experiments,XPS,ReactIR,ICP-AES,TEM,SEM,Raman and AFM.Heterogeneous catalytic process occurred at the interface of catalytic monolayer for the Suzuki coupling reaction could be proved.Introduction of non-precious metals enhanced the electronegativity of Pd by synergystics,thereby improving their catalytic activity and stability of the catalyst.The deactivation mechanism of GO@H-Fe95.7Pd4.26Ru0.01 and GO@T-Pd1Cu99 were also investigated,in which the accumulation and loss of active centers(metals)were the main reasons for the reduction of catalytic activity and stability. |
