Perovskite-Type Oxides La 0.6 M 0.4 Ni 0.6 Cu 0.4 O 3 (M = Ag, Ba, Ce) towards the Oxygen Reduction Reaction (ORR) in Alkaline Medium: Structural Aspects and Electrocatalytic Activity

摘要

In this work, La 0.6 M 0.4 Ni 0.6 Cu 0.4 O 3 (M = Ag, Ba, and Ce, denoted as LANC, LBNC, and LCNC, respectively) electrocatalysts were synthesized by the Pechini method at 1023 K for two hours in air. Rietveld refinement allowed the identification of the crystallographic phases present in all oxides. The electrocatalytic performance of these oxides towards the oxygen reduction reaction (ORR) was examined in alkaline medium by rotating disk electrode (RDE) technique and scanning electrochemical microscopy (SECM) in the redox competition mode. The results indicate that the best performance was found with the LANC electrocatalyst prepared with carbon as a conducting agent (LANC/Carbon), which showed good catalytic activity towards the ORR via a pseudo four-electron transfer pathway. The enhanced electrocatalytic activity of LANC is probably a result of the presence of a Ag phase, which improves the synergistic effect between the perovskite and carbon added to increase the conductivity, thus leading to a higher ORR performance when compared to other materials.