Coordination-Induced Reconstruction Optimizes Spatial Arrangements of Heterogeneous Yet Cooperative Sites to Boost...

Control over the spatial arrangement of heterogeneous yet cooperative sites is highly desirable yet challenging to enhance reaction kinetics. This study develops a coordination-induced reconstruction (CIR) strategy that, under a chloride atmosphere, in situ converts Fe nanoparticles into FeN₄Cl single atoms (SAs) and Fe atomic clusters (ACs) on nitrogen-doped carbon (NC), enabling several SAs around single ACs with an average distance of about 0.86 ± 0.08 nm. This spatial arrangement constitutes heterogeneous yet catalytically cooperative interfaces, enabling an efficient cascade of proton generation, proton transport, and oxygen hydrogenation at favorable sites with suitable distances, as revealed by operando infrared spectra, kinetic isotope effect, local pH measurements, and theoretical calculations. Resultant FeN₄Cl_SAs-Fe_ACs/NC remarkably enhances the oxygen reduction reaction (ORR) and steers it toward a 4-electron pathway with an ORR half-wave potential of 0.934 V, and robust stability for 50 000 cycles. The CIR strategy is effective for at least Ni- and Mn-based systems.