Hydrothermal co-doping of boron and phosphorus into porous carbons prepared from petroleum coke to improve oxidation resistance

摘要

Porous carbons (PC) have been extensively used in a wide variety of industries. However, their poor oxidation resistance, especially at high temperature (e.g.>370℃), has severely limited their applications such as catalysts under high temperature. Hydrothermal doping technology, as a newly emerged efficient approach for chemical modification, was for the first time introduced towards PC modification. The PCs used in this work were, by KOH activation, prepared from petroleum coke. The modified porous carbons (MPC) were achieved using hydrothermally co-doping boron and phosphorus into the PC followed by a heating treatment. The results revealed that the onset oxidation temperature of the MPC was greatly improved from 370 ℃ to 600 ℃. The residual weight percent for MPC, an immediate and most critical indication of the oxidation resistance, was observed as high as 49% at 850 ℃, while that of the blank sample was < 10% at an even lower temperature of 600 ℃. The achieved remarkable improvements on onset oxidation temperature and residue weight, substantiated by TGA, FTIR and Raman spectroscopy, confirmed the success of our unprecedented combination of co-doping and hydrothermal technologies to improve the oxidation resistances of PC materials.