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

Abstract

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.