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

Abstract

Dual-metal single-atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report ad ual-metal single-atom catalyst consisted of Cu À N 4 and Zn À N 4 on the N-doped carbon support (Cu/Zn À NC). It exhibits high-efficiency ORR activity with an E onset of 0.98 Vand an E 1/2 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.O perando XANES demonstrates that the CuÀN 4 as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn À N 4 during ORR process,a nd 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,s peeding up the process of rate determining step of OOH*.

An Adjacent Atomic Platinum Site Enables Single‐Atom Iron with High Oxygen Reduction Reaction Performance

“…Meanwhile, considering the much lower competitiveness of Pt‐N 4 to snatch O 2 than Fe‐N 4 active centers, [3e] O 2 molecules bonded with Pt‐N 4 center was not considered in the calculated reaction pathways. Based on these reasons, Fe‐N 4 is demonstrated as the only active center, while Pt‐N 4 is considered as the modulator (not active center) to tune the electronic state of Fe‐N 4 for the reaction pathway, which is completely different from the previously reported “synergetic effect” on the binary metal active centers, for example, Co‐Pt‐NC, [18] Fe‐Pt‐NC, [19] Fe‐Mn‐NC, [20] Fe‐Ni‐NC [21] and Cu‐N 4 /Zn‐N 4 , [22] Fe‐N 4 /Mn‐N 4 , [10b] Fe‐N 4 /Co‐N 4 [23] and Fe‐N 4 /Ni‐N 4 [2a, 11] et al. The theoretical η ORR of each catalyst can be determined by examining the reaction Gibbs free energies of the different mechanistic steps for Fe‐N 4 and Fe‐N 4 /Pt‐N 4 .…”

Identification of the Intrinsic Dielectric Properties of Metal Single Atoms for Electromagnetic Wave Absorption

“…3 d) and the coexistence of the Cu + and Cu 2+ species in Cu–N x C (Fig. 3 e) [ 24 ]. The valence states of the Mn, Co, and Ni species in Mn–N x C, Co–N x Cs, and Ni–N x Cs are + 2 (Fig.…”

Decreasing the coordinated N atoms in a single-atom Cu catalyst to achieve selective transfer hydrogenation of alkynes

“…Considering N atoms in pure CN being abundant, Cu centers in Cu 1 /CN can exist as Cu-N 3 and Cu-N 4 structures as commonly reported in previous studies of CN supported SA Cu catalysts. [56][57][58] For increasing unsaturated coordination sites, the Cu-N 2 structure of Cu centers may present in Cu 1 /CN/Al 2 O 3 . Therefore, since main N species in the CN of two catalysts being pyridinic-N, the potential Cu-N 4 , Cu-N 3 and Cu-N 2 structures with pyridinic-N coordination are simulated to explore their differences (Fig.…”