Atomically Dispersed Fe/N4 and Ni/N4 Sites on Separate-Sides of Porous Carbon Nanosheets with Janus Structure for Selective Oxygen Electrocatalysis.
Small
; 19(25): e2300289, 2023 Jun.
Article
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| MEDLINE
| ID: mdl-36929092
ABSTRACT
Dual single atoms catalysts have promising application in bifunctional electrocatalysis due to their synergistic effect. However, how to balance the competition between rate-limiting steps (RDSs) of reversible oxygen reduction and oxygen evolution reaction (OER) and fully expose the active centers by reasonable structure design remain enormous challenges. Herein, Fe/N4 and Ni/N4 sites separated on different sides of the carbon nanosheets with Janus structure (FeNijns /NC) is synthesized by layer-by-layer assembly method. Experiments and calculations reveal that the side of Fe/N4 is beneficial to oxygen reduction reaction (ORR) and the Ni/N4 side is preferred to OER. Such Janus structure can take full advantage of two separate-sides of carbon nanosheets and balance the competition of RDSs during ORR and OER. FeNijns /NC possesses superior ORR and OER activity with ORR half-wave potential of 0.92 V and OER overpotential of 440 mV at J = 10 mA cm-2 . Benefiting from the excellent bifunctional activities, FeNijns /NC assembled aqueous Zn-air battery (ZAB) demonstrates better maximum power density, and long-term stability (140 h) than Pt/C+RuO2 catalyst. It also reveals superior flexibility and stability in solid-state ZAB. This work brings a novel perspective for rational design and understanding of the catalytic mechanisms of dual single atom catalysts.
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MEDLINE
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En
Revista:
Small
Asunto de la revista:
ENGENHARIA BIOMEDICA
Año:
2023
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Article