Comparison of catalytic performance and coking resistant behaviors of cobalt- and nickel based catalyst with different Co/Ce and Ni/Ce molar ratio under SRE conditions

[Display omitted] •Co(Ni)-support interaction decreases with increase in Ce amount above Co(Ni)/Ce = 0.1.•Optimum Ce amount for performance in SRE corresponding to molar ratio metal/Ce = 0.1.•Ce amount influences on morphology of coke deposits of Ni catalysts.•The Ni catalysts were more capable of cleaving the CC bond in SRE than Co samples.•The coke deposited on Co and Ni catalysts in SRE differs the type and morphology. A series of Co-xCe/CeO2 and Ni-xCe/CeO2 catalysts with different ceria amount introduced from Ce(NO3)3 × 6H2O precursor, corresponding to Ce/Co(Ni) molar ratio from 0 to 1 were prepared by impregnation method. Among the tested catalysts, Co-0.1Ce/CeO2 and Ni-0.1Ce/CeO2 samples exhibited the smallest metal crystallites size, the strongest metal-support interaction, the best catalytic performance and the strongest resistance toward carbon deposition. Only an introduction of small amount of ceria from Ce(NO3)3 × 6H2O precursor led to an increase in the number of active sites for breaking CC and CH bonds. Too high Ce/Co molar ratio caused rapid deactivation of cobalt-based catalysts because of faster coverage of active sites by encapsulating carbon. Whereas too high Ce/Ni molar ratio generated the thick and long carbon filamentous deposits causing the nickel-based catalysts deactivation including not only the coverage of nickel species by carbon but also limitation of the contact of reactants with nickel species.