Pursuing complete and stable steam reforming of n-dodecane over nickel catalysts at low temperature and high LHSV

Abstract

Various nickel catalysts have been developed to pursue complete and stable steam reforming of n-dodecane at 923 K under high liquid hourly space velocity (LHSV) of 12 ml/gCat h and H2O/C of 4. Confinement of Ni nanoparticles by SBA-15, alloying of nickel and cobalt, and promotion of Ni-silica interaction by CeO2 have been adopted to improve catalytic 09performance of nickel. Ni, Ni-Co and CeO2-promoted Ni-Co supported on SBA-15 were prepared via a facile ethylene-glycol-assisted route. Various techniques including XRD, nitrogen adsorption–desorption, H2-TPR, TEM and TG/DTG were employed to characterize the fresh and spent catalysts. Results show that Ni/Ni-Co/Ni-Co-CeO2 nanoparticles are highly dispersed on mesoporous SBA-15 due to ethylene-glycol facilitation. Metal-support interaction is promoted by the presence of cobalt and CeO2. Steam reforming of n-dodecane was carried out to evaluate their catalytic performances under atmospheric pressure in a fixed-bed tubular reactor. The performance of nickel catalyst has been improved steadily by the support of SBA-15, alloying of Ni-Co and promotion of CeO2. Great enhancements of catalytic activity and stability have been achieved by these three strategies via effective inhibitions of Ni sintering and coke deposition. The catalyst of 3Ni-3Co-6CeO2@SBA-15 exhibits the highest conversion of n-dodecane (100%) and the best stability (only 7.5% deactivation in 7 h).