Stability of solid oxide fuel cell anodes based on YST-SDC composite with Ni catalyst

Ceramic material based on composite of yttria-doped SrTiO3 (YST) and samaria-doped ceria (SDC) incorporated with Ni catalyst has been evaluated as an anode of solid oxide fuel cell to substitute the use of conventional Ni-based cermets. The results indicated the advantages of suitable Ni addition which could remarkably enhance the electrochemical performance of anode due to the superior in catalytic activity of SDC and Ni towards fuel oxidation. Temperature-programmed reduction (TPR) profiles indicated the existence of bulk-free and interacted NiO in the composites. The cells with Ni/YST-SDC (20 wt% NiO) anodes exhibited stable performance in the prolong operation with tremendously severe conditions in methane fuel with low steam to carbon ratio (S/C = 0.1) and highly humidified hydrogen fuel (40% H2O-H-2) compared with the conventional Ni-based cermets. Small amount of deposited carbon was observed and played insignificant effects on the electrochemical performance after the operation for 100 h. The stable performance was ascribable to the excellence in YST-SDC ceramic framework that effectively suppressed the carbon formation. Furthermore, the Ni/YST-SDC anode showed high tolerance in encountering with the redox cycles. From these results, Ni/YST-SDC composite is considered to be a promising candidate for SOFC anode material operating in severe conditions. (C) 2012 Elsevier B.V. All rights reserved.