A Dual‐Atom La2 Catalyst for the Oxygen Reduction Reaction

Rare earth lanthanum element has large atomic radius, multi‐shell orbital electrons, and Fenton‐like reaction inertia, on which a localized high‐coordination structure can be easily formed for the favorable adsorption of reaction intermediates. However, for single‐atom lanthanum sites, due to the loss of all the outmost s and d electrons, the practically vacuous outmost orbitals are stable but sleepy for the oxygen reduction reaction (ORR). Here, we synthesize a novel dual‐atom La catalyst onto N‐doped graphene (La2‐NG) by a Joule ultrafast heating method, which shows a half‐wave potential of 0.893 V for the ORR. The La2‐NG‐assembled zinc‐air battery demonstrates a great open circuit voltage of 1.52 V and a maximal power density of 192 mW cm−2. Operando X‐ray absorption spectra reveal the change of valence states of La and the dynamic structural evolution of La2‐N6 moiety embedded onto the graphene during the ORR, through which the adsorption/desorption of oxygen reduction intermediates can be reasonably regulated. Theoretical calculations further demonstrate that the La2‐N6 structure can decrease the reaction energy barrier and promote charge transfer.