Electrocatalytic Properties of Nanocrystalline Calcium-Doped Lanthanum Cobalt Oxide for Bifunctional Oxygen Electrodes

Journal Article · Thu Apr 19 00:00:00 EDT 2012 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/jz300181a· OSTI ID:1211187

Malkhandi, S; Yang, B; Manohar, AK; Manivannan, A; Prakash, GKS; Narayanan, SR

Calcium-doped lanthanum cobalt oxide is a promising electrocatalyst for oxygen evolution and oxygen reduction in rechargeable metal air batteries and water electrolyzers operating with alkaline electrolyte. Nanocrystalline perovskite of composition La0.6Ca0.4CoO3 with a unique cellular internal structure was prepared at 350 degrees C and then annealed in air at progressively higher temperatures in the range of 600-750 degrees C. The samples were characterized by electrochemical techniques and X-ray photoelectron spectroscopy. The area-specific electrocatalytic activity for oxygen evolution/oxygen reduction, the oxidation state of cobalt, and the crystallite size increased with annealing temperature, while the Tafel slope remained constant. These trends provide new insights into the role of the cobalt center in oxygen evolution and oxygen reduction, and how preparation conditions can be altered to tune the activity of the cobalt center for electrocatalysis. We expect these findings to guide the design of electrocatalysts for bifunctional oxygen electrodes, in general.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: DE-AR0000136
• OSTI ID: 1211187
• Journal Information: Journal of Physical Chemistry Letters, Vol. 3, Issue 8; ISSN 1948-7185
• Country of Publication: United States
• Language: English