Surface engineering on MnO₂ nanorods by La single atoms to accelerate oxygen reduction kinetics

Surface engineering, which modulates the electronic structure and adsorption/desorption properties of electrocatalysts, is one of the key strategies for improving the catalytic performance. Herein, we demonstrate a facile solid-phase reaction for surface engineering of MnO₂ to boost the oxygen reduction kinetics. Via reaction with surface hydroxy groups, La single atoms with loading amount up to 2.7 wt% are anchored onto α-MnO₂ nanorods. After surface engineering, the oxygen reduction reaction (ORR) kinetics is significantly improved with the half-wave potential from 0.70 to 0.84 V, the number of transferred electrons from 2.5 to 3.9 and the limiting current density from 4.8 to 6.0 mA·cm⁻². In addition, the catalyst delivers superior discharge performance in both alkaline and neutral metal–air batteries. Density functional theory (DFT) calculations reveal that atomic La modulates the surface electronic configuration of MnO₂, reduces its d-band center and thus lowers the OOH* and O* reaction energy barrier. This work provides a new route for rational design of highly active electrocatalyst and holds great potential for application in various catalytic reactions.