Pd-promoted (La,Ca)(Cr,Mn)O3/GDC anode for hydrogen and methane oxidation reactions of solid oxide fuel cells

Abstract: La0.7Ca0.3Cr0.5Mn0.5O2.6/Gd-doped ceria (LCCM)/GDC composite oxides are developed as anodes for the hydrogen and methane oxidation reactions of solid oxide fuel cells (SOFCs). The composite anodes are sintered in temperatures range from 1150 to 1350°C and the lowest ohmic and polarization resistances of the cells are obtained on the anodes sintered at 1300°C. Electrode polarization resistance or area specific resistance (ASR) of the LCCM/GDC anode is 0.47Ωcm2 for the hydrogen oxidation reaction and ~2.2Ωcm2 for the methane oxidation reaction at 850°C. Addition of the Pd nanoparticles via a wet impregnation to the LCCM/GDC anodes decreases the ASR substantially to 0.15 and 0.23Ω cm2 for the hydrogen and methane oxidation reaction at 850°C, respectively. The reduction of the ASR is more pronounced for the methane oxidation reaction. The results indicate that the addition of Pd nanoparticles mainly affects the electrode process associated with the low frequencies, revealing the significant promotion effect of the impregnated Pd catalyst for the dissociation and diffusion processes of the hydrogen and methane oxidation reactions. The Pd-Impregnated LCCM/GDC composite anodes show a good stability in H2 and CH4 under conditions studied. [ABSTRACT FROM AUTHOR]