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It is important to tune the coordination configuration of dual‐atom catalyst (DAC), especially in the first coordination sphere, to render high intrinsic catalytic activities for oxygen reduction/evolution reactions (ORR/OER). Herein, a type of atomically dispersed and boron‐coordinated DAC structure, namely, FeN4B‐NiN4B dual sites, is reported. In this structure, the incorporation of boron into the first coordination sphere of FeN4/NiN4 atomic sites regulates its geometry and electronic structure by forming "Fe‐B‐N" and "Ni‐B‐N" bridges. The FeN4B‐NiN4B DAC exhibits much enhanced ORR and OER property compared to the FeN4‐NiN4 counterparts. Density functional theory calculations reveal that the boron‐induced charge transfer and asymmetric charge distributions of the central Fe/Ni atoms optimize the adsorption and desorption behavior of the ORR/OER intermediates and reduce the activation energy for the potential‐determining step. Zinc‐air batteries employing the FeN4B‐NiN4B cathode exhibit a high maximum power density (236.9 mW cm−2) and stable cyclability up to 1100 h. The result illustrates the pivotal role of the first‐coordination sphere of DACs in tuning the electrochemical energy conversion and storage activities. [ABSTRACT FROM AUTHOR]

Fe–N–C catalysts are emerging as promising alternatives to Pt‐based catalysts for the oxygen reduction reaction (ORR), while they still suffer from sluggish reaction kinetics due to the discontented binding affinity between the Fe‐N4 sites and oxygen‐containing intermediates, and unsatisfactory stability. Herein, a flexible multichannel carbon fiber membrane immobilized with atomically dispersed Fe‐N4 sites and neighboring Fe nanoclusters/nanoparticles (FeN4‐FeNCP@MCF) is synthesized. The optimized geometric and electronic structures of the Fe atomic sites brought by adjacent Fe nanoclusters/nanoparticles and hierarchically porous structure of the carbon matrix endow FeN4‐FeNCP@MCF with outstanding ORR activity and stability, considerably outperforming its counterpart with FeN4 sites only and the commercial Pt/C catalyst. Liquid and solid‐state flexible zinc–air batteries employing FeN4‐FeNCP@MCF both exhibit outstanding durability. Theoretical calculation reveals that the Fe nanoclusters can trigger remarkable electron redistribution of the FeN4 sites and modulate the hybridization of central Fe 3d and O 2p orbitals, facilitating the activation of O2 molecules and optimizing the adsorption capacity of oxygen‐containing intermediates on FeN4 sites, and thus accelerating the ORR kinetic. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with nanoclusters/nanoparticles for efficient ORR catalysis. [ABSTRACT FROM AUTHOR]