The effect of catalyst nanostructure on the performance of solid oxide fuel cell (SOFC) anodes prepared by infiltration of an electronic conductor (45 wt % La(0.8)Sr(0.2)Cr(0.5)Mn(0.5)O(3), LSCM) and a catalyst (1 wt % Pd and 9 wt % CeO(2)) into porous yttria-stabilized zirconia (YSZ) scaffolds was examined. When Pd and CeO(2) were added by classical infiltration with nitrate salts, the initial electrode impedance in 97% H(2)-3% H(2)O at 973 K was similar to 0.1 Omega cm(2); however, the impedance was found to increase significantly with time at 973 K and with heating to 1173 K. SEM images showed that the loss of performance coincided with a large increase in the size of the Pd crystallites. When Pd@CeO(2) dispersible core-shell structures obtained through self-assembly were infiltrated into the anode and used as the catalytic component, the initial performance was excellent and the activity was remarkably stable with time at 973 K and upon heating to 1173 K. The improved stability is shown to be the result of greatly suppressed particle-size growth for Pd@CeO(2) within the electrode structure. This study highlights the potential use of core-shell materials as stable structures in various fields of materials science and heterogeneous catalysis
Highly Active and Thermally Stable Core-Shell Catalysts for Solid Oxide Fuel Cells
CARGNELLO, MATTEO;FORNASIERO, Paolo;
2011-01-01
Abstract
The effect of catalyst nanostructure on the performance of solid oxide fuel cell (SOFC) anodes prepared by infiltration of an electronic conductor (45 wt % La(0.8)Sr(0.2)Cr(0.5)Mn(0.5)O(3), LSCM) and a catalyst (1 wt % Pd and 9 wt % CeO(2)) into porous yttria-stabilized zirconia (YSZ) scaffolds was examined. When Pd and CeO(2) were added by classical infiltration with nitrate salts, the initial electrode impedance in 97% H(2)-3% H(2)O at 973 K was similar to 0.1 Omega cm(2); however, the impedance was found to increase significantly with time at 973 K and with heating to 1173 K. SEM images showed that the loss of performance coincided with a large increase in the size of the Pd crystallites. When Pd@CeO(2) dispersible core-shell structures obtained through self-assembly were infiltrated into the anode and used as the catalytic component, the initial performance was excellent and the activity was remarkably stable with time at 973 K and upon heating to 1173 K. The improved stability is shown to be the result of greatly suppressed particle-size growth for Pd@CeO(2) within the electrode structure. This study highlights the potential use of core-shell materials as stable structures in various fields of materials science and heterogeneous catalysisPubblicazioni consigliate
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