Enhancing Oxygen Reduction Activity and CO₂ Tolerance by a Bismuth Doping Strategy for Solid Oxide Fuel Cell Cathodes

Layered perovskite related oxides, LnBaCo(2)O(5+delta) (Ln = rare-earth element) are potential ceramic cathodes for intermediate temperature solid oxide fuel cells. Herein, a simple way to tune the performance of NdBaCo2O5+delta (NBC) perovskite as a cathode by doping the Co-site with bismuth cation is reported. Compared with the parent oxide, the obtained stabilized double perovskites NdBaCo2-xBixO5+delta (x = 0.1 and 0.2) show a much improved electrocatalytic activity, achieving area-specific resistance of 0.268, 0.107 and 0.152 Omega cm(2) at 700 degrees C in air for NBC, x = 0.1, and 0.2, respectively. Density functional theory results demonstrate that bismuth doping effectively reduces the formation energy of oxygen vacancies. Moreover, the bismuth doping of NdBaCo2-xBixO5+delta cathode is much more robust against CO2 than that of NBC cathode. This work indicates that bismuth doping in the B-site of LnBaCo(2)O(5+delta) may be a highly attractive strategy for the future development of cathode materials.