Perovskite-Type Oxides La_0.6M_0.4Ni_0.6Cu_0.4O₃ (M = Ag, Ba, Ce) towards the Oxygen Reduction Reaction (ORR) in Alkaline Medium: Structural Aspects and Electrocatalytic Activity

Author(s)

Lima, Alan R. F. ; Lima, Alex S. ; Meloni, Gabriel N. ; Santos, Carla S. ; Bertotti, Mauro

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 32, n. 3, p. 10-pg., 2021-03-01.

Abstract

In this work, La0.6M0.4Ni0.6Cu0.4O3 (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. (AU)

• FAPESP's process: 15/20776-9 - Fabrication of nanometric probes for the study of biochemical processes by using Scanning Electrochemical Microscopy
• Grantee: Mauro Bertotti
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/02095-4 - Fabrication of nanosensors to be used in scanning electrochemical microscopy and further application in biological systems (single-cell analysis)
• Grantee: Alex da Silva Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/22396-6 - Development of a microsensor coupled to scanning electrochemical microscopy to investigate the role of mitochondria on the respiration process
• Grantee: Carla Santana Santos
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)