Cascade Synthesis of Fe-N-Fe Dual-Atom Catalysts for Superior Oxygen Catalysis.

Dual-atom catalysts (DACs) have been proposed to break the limitation of single-atom catalysts (SACs) in the synergistic activation of multiple molecules and intermediates, offering an additional degree of freedom for catalytic regulation. However, it remains a challenge to synthesize DACs with high uniformity, atomic accuracy, and satisfactory loadings. Herein, we report a facile cascade synthetic strategy for DAC via precise electrostatic interaction control and neighboring vacancy construction. We synthesized well-defined, uniformly dispersed dual Fe sites which were connected by two nitrogen bonds (denoted as Fe-N-Fe). The as-synthesized DAC exhibited superior catalytic performances towards oxygen reduction reaction, including good half-wave potential (0.91 V), high kinetic current density (21.66 mA cm), and perfect durability. Theoretical calculation revealed that the DAC structure effectively tunes the oxygen adsorption configuration and decreases the cleavage barrier, thereby improving the catalytic kinetics. The DAC-based zinc-air batteries exhibited impressive power densities of 169.8 and 52.18 mW cm at 25 °C and -40 °C, which is 1.7 and 2.0 times higher than those based on Pt/C+Ir/C, respectively. We also demonstrated the universality of our strategy in synthesizing other M-N-M DACs (M=Co, Cu, Ru, Pd, Pt, and Au), facilitating the construction of a DAC library for different catalytic applications.