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Free keywords:
High Single-Atom Loading, Oxygen Reduction Reaction, Pentacoordinated Configuration, Single-Atom Catalysts, Zinc-Air Battery, Atoms, Electrolytic reduction, Ligands, Loading, Oxygen, Zinc, Zinc air batteries, Zirconium, High single-atom loading, O ligands, Oxygen reduction reaction, Pentacoordinated, Pentacoordinated configuration, Single-atom catalyst, Single-atoms, Zinc-air battery, ]+ catalyst, Catalysts
Abstract:
Single-atom catalysts (SACs), as promising alternatives to Pt-based catalysts, suffer from the limited choice of center metals and low single-atom loading. Here, we report a pentacoordinated Zr-based SAC with nontrivial axial O ligands (denoted O−Zr−N−C) for oxygen reduction reaction (ORR). The O ligand downshifts the d-band center of Zr and confers Zr sites with stable local structure and proper adsorption capability for intermediates. Consequently, the ORR performance of O−Zr−N−C prominently surpasses that of commercial Pt/C, achieving a half-wave potential of 0.91 V vs. reversible hydrogen electrode and outstanding durability (92 % current retention after 130-hour operation). Moreover, the Zr site shows good resistance towards aggregation, enabling the synthesis of Zr-based SAC with high loading (9.1 wt%). With the high-loading catalyst, the zinc-air battery (ZAB) delivers a record-high power density of 324 mW cm−2 among those of SAC-based ZABs. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.
