Defect-Engineered IrO_x@Perovskite Heterostructures via Thermal Reconstruction for Acid-Stable Oxygen Evolution...

Perovskite-type oxides hold promise as supports for Ir-based acidic oxygen evolution reaction (OER) catalysts, yet their instability under harsh conditions limits practical application. Defect engineering of IrO_x-perovskite heterostructures offers new opportunities for acidic oxygen evolution catalysis. Here, we demonstrate thermal-reconstructed oxygen defect regulation in IrO_x@La_1.2Sr_0.8Ni_0.6Fe_0.4O_4+δ (IrO_x@LSNF) catalysts, where controlled calcination induces in situ growth of oxygen-deficient amorphous IrO_x on Ruddlesden-Popper perovskite. Thermal reconstruction at 250°C generates oxygen-defect-rich amorphous IrO_x on LSNF (IrO_x@LSNF-250), creating strong metal-metal oxides support interaction (MMSI) that enhances active-site utilization while favoring the lattice oxygen participation mechanism (LOM) for superior OER activity. Remarkably, the perovskite-anchored IrO_x heterostructure maintains considerable durability in half-cell acidic media against LOM-induced collapse, demonstrating how defect-engineered thermal reconstruction simultaneously addresses activity-stability trade-offs in acidic OER catalysis. The optimized OER performance of IrO_x@LSNF-250 in acidic media are attributed to perovskite-anchored Ir species suppressing dissolution, together with thermal-reconstruction-enriched oxygen defects optimizing LOM. This work establishes a paradigm for defect-engineered heterostructures via thermal reconstruction, advancing perovskite-based OER catalysts beyond conventional stability-activity trade-offs in acidic media.