Pretreatment of cylindrical coconut activated carbon and performance as catalyst support
Cylindrical coconut activated carbon(CCAC) support was graphitized at a high temperature(1900 °C) in argon, then oxidized with an O2-N2-H2O mixture, and treated with nitric acid. Pretreatment of carbon support on its mechanical strength, physical structure, chemical composition and surface properties of cylindrical CCAC support was investigated by X-ray diffraction(XRD), surface area analysis, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), thermogravimetric-differential thermogravimetric(TG-DTG) analysis and temperature programmed desorption-mass spectrometry(TPD-MS), and the effect of CCAC support on the catalytic activities was also studied. The results show that the degree of graphitization, the purity(phosphorus, sulphur), pore structure(micropore, mesopore) and oxygen-containing functional groups(—COOH, —OH, —COOR) of carbon supports are obviously different, which have a great influence on the performance of Ru-based catalysts. After a series of pretreatments, the surface physical and chemical properties of the commercial CCAC are modified and improved, and the activity of as-prepared Ru/AC catalyst is increased significantly.