Fabrication and catalytic properties of “cage like” aryl imine Pd(II)/Cu(II)-bimetallic catalytic monolayer supported on graphene oxide for Suzuki coupling reaction

Abstract

A new aryl triimine palladium-copper bimetallic catalytic molecular monolayer anchored on graphene oxide (denoted as [email protected]0.01/Cu0.99) was fabricated by self-assembly and characterized by XRD, Raman, FT-IR, XPS, SEM, TEM, ICP-AES and AFM. Its catalytic performance, stability and catalytic mechanism were investigated by using Suzuki coupling reaction as a template. [email protected]0.01/Cu0.99 exhibited high catalytic activity for iodo aromatics and brominated aromatics with a higher TOF (118588 h−1) and could be recycled for 6 times without significant loss of activity. Heterogeneous catalytic mechanism was investigated in detail by kinetic and thermal filtration experiments, catalyst poisoning experiments and XPS, with which heterogeneous catalytic process occurred at the interface of catalytic monolayer could be confirmed. Hybrid of non-precious metals enhanced the electronegativity of Pd by synergistic between Pd and Cu, thereby improving their catalytic activity and stability of the catalyst. The deactivation mechanism of [email protected]0.01/Cu0.99 was the accumulation and loss of active centers during catalytic process.