Study of ceria-supported nickel catalyst and effect of yttria doping on carbon dioxide reforming of methane

Carbon dioxide reforming of methane was studied over Ni supported on ceria and yttria-doped ceria (YDC) to seek insight into the effect of catalysis a t the metal-support interface. In contrast to the performance of Ni/gamma - Al2O3, which displayed very rapid deactivation with time on stream, the rat e over the ceria- or YDC-supported catalysts exhibited exceptional enhancem ent of activity and coking resistivity. The extent of enhancement decreased with increased yttria loading. The enhancement of activity and coking resi stivity of the ceria-based catalysts, coupled with the results of temperatu re-programmed reduction and hydrogenation, suggested the formation of inter facial active centers and the existence of metal-support interaction, which decreased with increased yttria loading. EPR and XPS results provided evid ence that the ability Of CeO2 to lose its lattice oxygen to form Ce3+ was i nhibited with yttria doping. The lattice oxygen of ceria is inferred to hav e played some positive role in the activation of both CH4 and CO2; such pro motion is attributed in part to the availability of Ce3+ species at the met al-support inter-face. (C) 2001 Elsevier Science B.V. All rights reserved.