Engineering Atomic Sites via Adjacent Dual‐Metal Sub‐Nanoclusters for Efficient Oxygen Reduction Reaction and Zn‐Air Battery

Abstract

N‐coordinated transition‐metal materials are crucial alternatives to design cost‐effective, efficient, and highly durable catalysts for electrocatalytic oxygen reduction reaction. Herein, the synthesis of uniformly distributed Cu−Zn clusters on porous N‐doped carbon, which are accompanied by Cu/Zn‐Nx single sites, is demonstrated. X‐ray absorption fine structure tests reveal the co‐existence of M−N (M = Cu or Zn) and M−M bonds in the catalyst. The catalyst shows excellent oxygen reduction reaction (ORR) performance in an alkaline medium with a positive half‐wave potential of 0.884 V, a superior kinetic current density of 36.42 mA cm−2 at 0.85 V, and a Tafel slope of 45 mV dec−1, all of which are among the best‐reported results. Furthermore, when employed as an air cathode in Zn‐Air battery, it reveals a high open‐cycle potential of 1.444 V and a peak power density of 164.3 mW cm−2. Comprehensive experiments and theoretical calculations approved that the high activity of the catalyst can be attributed to the collaboration of the Cu/Zn‐N4 sites with CuZn moieties on N‐doped carbons.

Formaldehyde Oxidation over Co@N-Doped Carbon at Room Temperature: Tunable Co Size and Intensified Surface Electron Density

“…The similar variation trend of Co–N x contents from Co@NC-1.0 to Co@NC-0.05 can validate this explanation. The N 1s spectra in Figure c showed five peaks at 398.6 ± 0.2, 399.6 ± 0.1, 400.6 ± 0.2, 401.4 ± 0.1, and 403.3 ± 0.2 eV, arising due to the pyridinic N, Me–N (Me = Co or Zn), pyrrolic N, graphitic N, and oxidic N, respectively. , The increased amounts of surface N elements would induce the variation in content of different kinds of nitrogen species (Table ). The O 1s spectra for all of these catalysts showed two peaks located around 531.0 and 532.5 eV (Figure d).…”

Electronic Metal–Support Interaction Modulation of Single‐Atom Electrocatalysts for Rechargeable Zinc–Air Batteries

“…[36,126] In addition, some potential guest groups, such as small molecules and inorganic particles, can be further grafted on the center metal atoms due to their unsaturated coordination. [41,127] The changes in the coordination structures affects the electronic structure of the active centers and regulate their intrinsic activity. Furthermore, carbon-support materials for ORR and OER should possess high porosity, high conductivity, a large surface area, and high electrochemical stability.…”

Synergistically enhanced iron and zinc bimetallic sites as an advanced ORR electrocatalyst for flow liquid rechargeable Zn–air batteries

“…Notably, a low amount of Zn sites could be left due to the partial evaporation of Zn atoms (boiling point: 907 °C) under the annealing process. 26 Additionally, the chemical structure of TA–Fe–PI was confirmed by FT-IR spectroscopy, as shown in Fig. 1b.…”

“…23,24 Additionally, Zn–Cu dual-metal atom catalysts exhibit high-efficiency ORR activity and stability, attributed to the adjustment effect of Zn on the d-orbital electron distribution of Cu, resulting in the stretching and cleavage of the O–O bond on Cu active sites, dropping the free energies of key intermediates (OOH* and O*), and the reversible transformation from single atoms to clusters during the ORR. 25,26 Generally, the ORR electrocatalytic activity of M–N x –C catalysts follows the order of Fe > Co > Cu > Mn > Ni. 27 Besides, in the universal ORR activity volcano relationship, Fe species are preferred candidates for catalyst design despite the N coordination configuration (pyrrole-4N and pyridine-4N coordination), attributed to the strong adsorption to OH*.…”