Electrochemical performance and carbon deposition resistance of M-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (M=Pd, Cu, Ni or NiCu) anodes for solid oxide fuel cells

Pd-, Cu-, Ni- and NiCu-BaZr0.1Ce0.7Y0.1Yb0.1O3-delta anodes, designated as M-BZCYYb,were prepared by impregnating M-containing solution into BZCYYb scaffold, and investigated in the aspects of electrocatalytic activity for the reactions of H-2 and CH4 oxidation and the resistance to carbon deposition. Impregnation of Pd, Ni or NiCu significantly reduced both the ohmic (RV) and polarization (R-Omega) losses of BZCYYb anode exposed to H-2 or CH4, while Cu impregnation decreased only R-Omega in H-2 and the both in CH4. Pd-, Ni- and NiCu-BZCYYb anodes were resistant to carbon deposition in wet (3 mol. % H2O) CH4 at 750 degrees C. Deposited carbon fibers were observed in Pd- and Ni-BZCYYb anodes exposed to dry CH4 at 750 degrees C for 12 h, and not observed in NiCu-BZCYYb exposed to dry CH4 at 750 degrees C for 24 h. The performance of a full cell with NiCu-BZCYYb anode, YSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-delta-Gd doped CeO2 (LSCF-GDC) cathode was stable at 750 degrees C in wet CH4 for 130 h, indicating that NiCu-BZCYYb is a promising anode for direct CH4 solid oxide fuel cells (SOFCs).