Facile controlled formation of CoNi alloy and CoO embedded in N-doped carbon as advanced electrocatalysts for oxygen evolution and zinc-air battery

•A facile and controllable strategy toward alloy/metal oxide embedded in N-doped carbon is presented.•CoO is in-situ formed during the preparation of CoNi without further annealing in air.•Schottky barrier between CoNi and CoO favors charge separation, enhancing the catalytic OER activity and kineti...

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Veröffentlicht in:Electrochimica acta 2021-11, Vol.395, p.139204, Article 139204
Hauptverfasser: Ao, Kelong, Daoud, Walid A.
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Sprache:eng
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Zusammenfassung:•A facile and controllable strategy toward alloy/metal oxide embedded in N-doped carbon is presented.•CoO is in-situ formed during the preparation of CoNi without further annealing in air.•Schottky barrier between CoNi and CoO favors charge separation, enhancing the catalytic OER activity and kinetics.•Catalytic performance exceeds analogous catalysts as well as commercial RuO2. Constructing Schottky barrier of alloy/metal oxide interfaces is an emerging approach to design electrocatalysts with desired performance. Herein, a nitrogenous organic modified bimetal layered hydroxide salts (LHS) precursor is used to prepare CoNi alloy and CoO coupled nitrogen-doped carbon (NC) hybrids on carbon paper (CP) via a one-step pyrolysis at only 500 °C. Through adjusting the metal molar ratio in LHS precursor and the pyrolysis temperature, CoO is in-situ produced during pyrolysis. Since both alloy and metal oxide possess potential oxygen evolution reaction activity, the resulting CoNi-CoO@NC/CP exhibits enriched electrochemical active surface area, small overpotential (309 mV) at current density of 10 mA cm−2, low Tafel slope (67.7 mV dec−1), and good durability for 64 h at ∼20 mA cm−2 in 1.0 M KOH. Furthermore, a zinc-air battery based on this catalyst shows a high specific power of 96.2 W gcat−1, which exceeds that of conventional RuO2+Pt/C catalyst (66.8 W gcat−1). This work provides an appealing approach for the development of highly efficient alloy/metal oxide electrocatalysts for rechargeable metal-air battery. A novel CoNi-CoO@NC/CP Schottky electrocatalyst is developed using a facile, controllable strategy. Owing to electron redistribution at the interface of CoNi alloy and CoO, CoNi-CoO@NC/CP exhibits enhanced electrocatalytic performance toward oxygen evolution reaction, and as air cathode in rechargeable zinc-air battery, outperforms counterparts based on RuO2+Pt/C. [Display omitted]
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2021.139204