Strong Heteroatomic Bond‐Induced Confined Restructuring on Ir‐Mn Intermetallics Enable Robust PEM Water Electrolyzers

Abstract

Low‐iridium acid‐stabilized electrocatalysts for efficient oxygen evolution reaction (OER) are crucial for the market deployment of proton exchange membrane (PEM) water electrolysis. Manipulating the in situ reconstruction of Ir‐based catalysts with favorable kinetics is highly desirable but remains elusive. Herein, we propose an atomic ordering strategy to modulate the dynamic surface restructuring of catalysts to break the activity/stability trade‐off. Under working conditions, the strong heteroatom‐bonded structure triggers rational surface‐confined reconstruction to form self‐stabilizing amorphous (oxy)hydroxides on the model Ir‐Mn intermetallic (IMC). Combined in‐situ/ex‐situ characterizations and theoretical analysis demonstrate that the induced strong covalent Ir‐O‐Mn units in the catalytic layer weaken the formation barrier of OOH* and promote the preferential dynamic replenishment/conversion pathway of H2O molecules to suppress the uncontrollable participation of lattice oxygen (about 2.6 times lower than that of pure Ir). Thus, a PEM cell with Ir‐Mn IMC as anode “pre‐electrocatalyst” (0.24 mgIr cm−2) delivers an impressive performance (3.0 A cm−2@1.851 V@80 °C) and runs stably at 2.0 A cm−2 for more than 2,000 h with the cost of USD 0.98 per kg H2, further validating its promising application. This work highlights surface‐confined evolution triggered by strong heteroatom bonds, providing insights into the design of catalysts involving surface reconstruction.