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Oxygen reduction reaction activity of La-based perovskite oxides in alkaline medium : a thin-film rotating ring-disk electrode study

journal contribution
posted on 09.02.2012, 00:00 authored by Jaka Sunarso, Angel TorrieroAngel Torriero, W Zhou, Patrick HowlettPatrick Howlett, Maria ForsythMaria Forsyth
In this work, LaMO3 and LaNi0.5M0.5O3 (M = Ni, Co, Fe, Mn and Cr) perovskite oxide electrocatalysts were synthesized by a combined ethylenediaminetetraacetic acid-citrate complexation technique and subsequent calcinations at 1000 °C in air. Their powder X-ray diffraction patterns demonstrate the formation of a specific crystalline structure for each composition. The catalytic property of these materials toward the oxygen reduction reaction (ORR) was studied in alkaline potassium hydroxide solution using the rotating disk and rotating ring-disk electrode techniques. Carbon is considered to be a crucial additive component because its addition into perovskite oxide leads to optimized ORR current density. For LaMO3 (M = Ni, Co, Fe, Mn and Cr)), in terms of the ORR current densities, the performance is enhanced in the order of LaCrO3, LaFeO3, LaNiO3, LaMnO3, and LaCoO3. For LaNi0.5M0.5O3, the ORR current performance is enhanced in the order of LaNi0.5Fe0.5O3, LaNi0.5Co0.5O3, LaNi0.5Cr0.5O3, and LaNi0.5Mn0.5O3. Overall, LaCoO3 demonstrates the best performance. Most notably, substituting half of the nickel with cobalt, iron, manganese, or chromium translates the ORR to a more positive onset potential, suggesting the beneficial catalytic effect of two transition metal cations with Mn as the most promising candidate. Koutecky–Levich analysis on the ORR current densities of all compositions indicates that the four-electron pathway is favored on these oxides, which are consistent with hydroperoxide ion formation of <2%.

History

Journal

Journal of physical chemistry C

Volume

116

Issue

9

Pagination

5827 - 5834

Publisher

American Chemical Society

Location

Washington, D. C.

ISSN

1932-7447

eISSN

1932-7455

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2012, American Chemical Society