Immobilization Of Graphene Oxide On The Surface Of Cordierite And Its Catalytic Performance

Due to its extraordinary two-dimensional structure, large specific surface area and diverse surface functional groups, graphene oxide (GO) are expected as a promising catalytic support. However, GO suffer from the separation problem when they are used in liquid or gas reactions because of the tiny size. Therefore the prerequisite for exploiting practical applications for graphene as catalytic support is the immobilization on a structured substrate. Pd/graphene/cordierite monolithic catalysts were prepared in this paper. Hydrogenation of styrene (PE) and catalytic combustion of toluene are chosen as the model reaction. The main work and conclusion are as follow:Firstly, we demonstrate that GO nanosheets can be readily immobilized on the surface of inner channels of cordierite via ultra-sonic impregnation method without any stabilizer. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) were characterized Pd/graphene/cordierite monolithic catalysts, nuclear magnetic resonance (NMR) and FT-IR characterization revealed that GO nanosheets were probably immobilized on the cordierite surface by hydrogen bonding. And the highest PE reaction activity95.2mmol PE/(min·g) of Pd was obtained.Furtherly, we prepared the monolithic catalyst with the assistance of PDDA. GO was charactized by FT-IR. X-ray photoelectron spectroscopy (XPS) were used to character catalyst. The results show that the strong electron-withdrawing ability of PDDA leads to the occurrence of charge transfer from both cordierite and graphene to the N species of PDDA. graphene was firmly immobilized with introduction of PDDA. And a highly stable and active Pd catalyst on monolithic cordierite with graphene coating was prepared with the assistance of PDDA. TEM showed Pd a uniform size of less than5nm. The effects of modified amount of solvent, precursor, ultrasonic time and ultrasonic power on the activity of catalysts were investigated. The results show that a highly stable and active Pd catalyst on monolithic cordierite with graphene coating was prepared with the assistance of PDDA. The highest activity162mmol PE/(min·g) of Pd was obtained. Catalytic combustion of toluene ignition temperature120℃, completed combustion temperature260℃. In conclusion, a new promising technique to prepare Pd/graphene/cordierite monolithic with good activity was achieved in this study.