Cations in Octahedral Sites: A Descriptor for Oxygen Electrocatalysis on Transition‐Metal Spinels

Exploring efficient and low‐cost electrocatalysts for the oxygen‐reduction reaction (ORR) and oxygen‐evolution reaction (OER) is critical for developing renewable energy technologies such as fuel cells, metal–air batteries, and water electrolyzers. A rational design of a catalyst can be guided by identifying descriptors that determine its activity. Here, a descriptor study on the ORR/OER of spinel oxides is presented. With a series of MnCo 2 O 4 , the Mn in octahedral sites is identified as an active site. This finding is then applied to successfully explain the ORR/OER activities of other transition‐metal spinels, including Mn x Co 3− x O 4 ( x = 2, 2.5, 3), Li x Mn 2 O 4 ( x = 0.7, 1), XCo 2 O 4 (X = Co, Ni,…

• NS
  National Science Foundation
• UD
  U.S. Department of Energy
• UD
  U.S. Department of Commerce
• D
  DuPont
• NU
  Northwestern University
• NR
  National Research Foundation
• NR
  National Research Foundation Singapore
• MO
  Ministry of Education - Singapore

  Awards: RG131/14, MOE2015‐T2‐1‐020
• MO
  Ministry of Education, India
• DO
  Division of Materials Research