Tailoring the Chemisorption Manner of Fe d-Band Center with La2O3 for Enhanced Oxygen Reduction in Anion Exchange Membrane Fuel Cells

Engineering the electronic configuration and intermediates adsorption behaviors of high-performance non-noble-metal-based catalysts for the sluggish oxygen reduction reaction (ORR) kinetics at the cathode is highly imperative for the development of anion exchange membrane fuel cells (AEMFCs), yet remains an enormous challenge. Herein, a rare-earth metal oxide engineering tactic through the formation of Fe3O4/La2O3 heterostructures in N,O-doped carbon nanospheres (Fe3O4/La2O3@N,O-CNSs) for efficient oxygen reduction electrocatalysis is reported. The theoretical calculations reveal that the interfacial bonds formed by the La & horbar;O & horbar;Fe heterogeneous interface effectively optimize the electronic structure of the Fe d-band center relative to the Fermi level, which results in a significant reduction of the reaction barriers of rate-limiting steps during the ORR. The modulation in intermediates chemisorption enables Fe3O4/La2O3@N,O-CNSs an outstanding ORR performance and improved stability, with a significantly higher half-wave potential value (0.88 V). More impressively, this integrated catalyst delivers a remarkable power density of 148.7 mW cm(-2) in practical AEMFC operating conditions, along with negligible performance degradation over 100 h using an H-2-air atmosphere, which is higher than commercial Pt/C-coupled electrodes. The results presented here are believed to provide guidelines for fabricating high-performance AEMFCs electrocatalysts in terms of heterointerface engineering and strong electronic coupling effect induced by rare-earth oxides.