Revealing the Dominant Chemistry for Oxygen Reduction Reaction on Small Oxide Nanoparticles

The bulk chemistry has been successfully used as a descriptor for oxygen reduction reaction (ORR) activities of various metal oxides. However, as the size of oxides becomes small, the bulk chemistry may not be sufficient to describe the activities. Here, we report a systematic study on Mn-substituted ferrite MnxFe3–xO4 (x = 0.5–2.5) nanoparticles and the roles of surface Mn in determining their ORR activities. Gradual Mn substitution induced...