Preparation And Oxidation Resistance Of Petroleum Coke-based Porous Carbon

With abundant pores, good mechanical property and high chemical stability, porouscarbons (PCs) have been widely used in the fields of adsorption, separation, electronics,energy storage and catalyst. The poor oxidation resistance of PCs at high temperature hasgreatly restrained their industrial applications in oxygen-exposed environments. To improvethe oxidation resistance of PCs is one of the hot topics in the field of carbon materials.Petroleum coke, a byproduct in oil refining with large quantity and high carbon content,is an excellent raw material for the preparation of PCs. Coconut shell, as a biomass wastewith large amount and hard texture, can be used to make PCs with high quality. In this paper,PCs were prepared from petroleum coke via chemical activation method with KOH as activeagent. In order to improve the oxidation resistance of PCs with different surface area, boronand phosphorus were added to PCs by impregnation co-doping, hydrothermal co-doping andsolid boron-doping. PCs were characterized by X-ray diffraction, energy dispersivespectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electronmicroscope, nitrogen adsorption and thermo gravimetric analysis, etc.The results showed that the optimized preparation parameters of PC from petroleum cokeare as follows: carbonization temperature is500°C, activation temperature and time are850°C and2h, respectively. The anti-oxidation ability of PCs was effectively increased byco-doping. The composition and microscopic structure of co-doped PCs were both changed.The relative weight loss of PC from petroleum coke at500oC decreased from94.6%of rawPC to14.0%of impregnation co-doping PC at. The relative weight loss of PC frompetroleum coke at500oC decreased from94.6%of raw PC to16.7%of hydrothermalco-doping PC at500oC. For solid boron-doping, B4C was used as the additive when heating by electric furnace and the relative weight loss of coconut shell-based PC decreased from63.5%of raw PC to19.6%of doped PC at500oC. While when heated by microwave, B4Cand B2O3as the additive, the relative weight loss of coconut shell-based PC decreased from63.5%of raw PC to8.6%of doped PC at500oC.All doping methods including impregnation co-doping, hydrothermal co-doping andsolid boron-doping can improve the oxidation resistance of PCs at high temperature.Hydrothermal co-doping is most suitable for PC with high surface area. Besides, the SBETandtotal volume of PCs both changed after doping. The hydrothermal co-doping has the smallesteffect on the SBETand total volume of PCs among above three doping methods.