Breaking Charge Symmetry in Co–Zn Dual‑Atom Catalyst With Axial Sulfur Coordination for Efficient Oxygen Reduction Reaction

Abstract

ABSTRACT Dual‐atom catalysts (DACs) represent an emerging and promising paradigm in electrocatalysis. Nevertheless, their symmetric electron density distribution hampers the polarization and subsequent scission of the O─O bond. In this work, a Co–Zn DAC with axial sulfur coordination (Co─Zn@SNC) was constructed via a molecular‐cage encapsulation method. The as‐synthesized catalyst demonstrated outstanding oxygen reduction reaction (ORR) activity across a wide pH range, with half‐wave potentials of 0.902 V in 0.1 M KOH, 0.817 V in 0.1 M PBS, and 0.809 V in 0.1 M HClO 4 . Theoretical calculations revealed that the axially coordinated S not only modulated the orbital and electronic structure of the Co active center but also collaborated with the nearby Zn site to induce an asymmetric charge distribution within the Co‐N 4 , thereby shifting the catalytic activity closer to the peak of the Sabatier volcano plot. The zinc–air battery (ZAB) and microbial fuel cell (MFC) assembled with the Co─Zn@SNC cathode exhibited peak power densities of 166.36 mW cm −2 and 1.505 W m −2 , respectively, as well as good stability. The present work provided fundamental insights into the precise regulation and underlying mechanism of DACs, offering a viable strategy for the rational design of advanced electrocatalysts for energy storage and conversion applications.