Effect of Ni-loading on Sm-doped CeO₂ anode for ammonia-fueled solid oxide fuel cell

Abstract

Samaria-doped ceria, (SmO_1.5)_0.2(CeO₂)_0.8 (SDC), containing nickel (Ni) was prepared as the anode of solid oxide fuel cell fueled with 6% ammonia (NH₃). The Ni-free SDC powders prepared by the reverse co-precipitation method exhibited poor catalytic activities for NH₃ decomposition in 6% NH₃/Ar. Impregnation of Ni onto the SDC powders significantly enhanced its catalytic activity. The catalytic activity was highest at 10 wt % Ni–SDC, but it decreased with an increase in the Ni content. Contrary to expectation, the anodic performances were similar between 10 and 40 wt % of Ni loading and the highest maximum power densities were 98.8 and 96.5 mW·cm⁻² at 900°C, respectively. Impedance analysis of the anodes revealed that the anodic performance was rate-controlled by the similar process in 4%H₂ fuel and that was electrochemical oxidation and diffusion processes.