ScholarWorks@중앙대학교

초록

Single-atom catalysts (SACs) have attracted considerable attention as promising substitutes for noble metal catalysts in the oxygen reduction reaction (ORR) due to their exceptional atom utilization efficiency and tunable coordination environments. SACs are typically supported on conductive materials to enhance electron transport, with carbon nanotubes (CNTs) commonly used for this purpose. However, this study revealed that CNTs play a dual role: improving conductivity and modulating the coordination structure of SACs. Using advanced X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations, we demonstrated that CNTs alter the Fesingle bondN bond length and increase the structural instability, resulting in enhanced intrinsic catalytic properties of MOF-derived Fesingle bondN3 SACs (FeSA@NC/CNT). Correspondingly, electrochemical analyses confirm that the ORR performance of FeSA@NC/CNT is comparable to that of commercial Pt/C catalyst, achieving a half-wave potential of 0.87 V and a kinetic current density of 4.12 mA cm−2 at 0.9 V. In Zn–air batteries, FeSA@NC/CNT achieves a maximum power density of 188 mW cm−2 and a specific capacity of 823 mA h gZn−1, along with remarkable stability over 600 charge–discharge cycles. This study highlights the transformative potential of CNT integration into SAC catalysts and establishes a new pathway for the development of sustainable energy technologies.

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