La-Co-Mn oxide aerogels as high-performance electrocatalysts for anion exchange membrane water electrolysis

In this work, mixed Mn Co and La–Co–Mn oxide aerogels were synthesized via a microwave-assisted sol–gel method to develop high-performance oxygen evolution reaction (OER) catalysts for anion exchange membrane water electrolysis. Both materials exhibited mesoporous structures and high crystallinity; however, the LaCoMnO₃ perovskite showed outstanding electrochemical performance, achieving an industrial-grade current density of 5.65 A cm −2 at 2.2 V. This superior activity—surpassing even commercial IrO₂ benchmarks under high-current conditions—is supported by an exceptionally low charge-transfer resistance of 0.08 Ω·cm 2 , as revealed by electrochemical impedance spectroscopy (EIS), indicating significantly accelerated OER kinetics compared with the MnCo₂O₄ spinel. The enhanced performance is attributed to a synergistic combination of the high-surface-area aerogel morphology and a high density of surface oxygen vacancies (O V /O L = 1.71) induced by intentional La deficiency, which promotes a transition toward the lattice oxygen mechanism (LOM). Furthermore, the La–Co–Mn oxide aerogel catalyst demonstrated robust stability over 500 h under dynamic operating conditions, highlighting its strong potential for sustainable, large-scale hydrogen production.