Revealing the interfacial electron modulation effect of CoFe alloys with CoC encapsulated in N-doped CNTs for superior oxygen reduction
Jing Sun, Niankun Guo, Tianshan Song, Yi‐Ru Hao, Jiawen Sun, Hui Xue, Qin Wang
Abstract
Rationally designing and developing robust and durable electrocatalytic materials for oxygen reduction/evolution are essential for metal−air batteries. Herein, an effective approach is proposed to fabricate high-performance electrocatalysts based on CoFe alloy and CoCX nanoparticles sandwiched in nitrogen-doped carbon nanotubes. The preparation of CoFe−CoCX@NCNT is achieved by the calcination of CoFe2O4 spinel and dicyandiamide under reducing atmosphere. The CoFe−CoCX@NCNT catalyst exhibits remarkable oxygen reduction reaction (ORR) performance with the onset and half-wave potential of 1.01 V and 0.89 V, respectively, exceeding the commercial Pt/C catalyst. Furthermore, the Zn−air battery using CoFe−CoCX@NCNT as air cathode shows a power density of 175 mW cm−2, which is also higher than that of the industrial Pt/C + RuO2. The super electrocatalytic performance is attributed to the multiple heterointerface and strong coupling effect among CoFe, CoCX, and NCNT, which can regulate conductivity and electron structure of the catalyst. This study supplies a practical strategy to exploit active and low-cost catalytic material for Zn−air batteries, and presents an in-depth insight into the designing of efficient green energy storage devices.