Operando Cooperated Catalytic Mechanism of Atomically Dispersed Cu−N4 and Zn−N4 for Promoting Oxygen Reduction Reaction

Abstract

AbstractDual‐metal single‐atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual‐metal single‐atom catalyst consisted of Cu−N4 and Zn−N4 on the N‐doped carbon support (Cu/Zn−NC). It exhibits high‐efficiency ORR activity with an Eonset of 0.98 V and an E1/2 of 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state‐of‐the‐art Pt/C and great mass of Pt‐free single atom catalysts. Operando XANES demonstrates that the Cu−N4 as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn−N4 during ORR process, and then turns to single atom state again after reaction. DFT calculation further indicates that the adjustment effect of Zn on the d‐orbital electron distribution of Cu could benefit to the stretch and cleavage of O‐O on Cu active center, speeding up the process of rate determining step of OOH*.