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In Situ‐Grown Nitrogen‐Doped Carbon‐Nanotube‐Embedded Two Phases of Bimetal CoFe Alloy and CoFe 2 O 4 Spinel Oxide as Highly Efficient Bifunctional Catalyst for Oxygen Reduction and Evolution Reactions in Rechargeable Zinc–Air Batteries
Author(s) -
Kone Issa,
Ahmad Zubair,
Xie Ao,
Kong Lingpo,
Tang Yang,
Sun Yanzhi,
Chen Yongmei,
Yang Xiaojin,
Wan Pingyu
Publication year - 2021
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202001117
Subject(s) - bimetal , bifunctional , materials science , carbon nanotube , catalysis , cobalt , chemical engineering , spinel , oxide , reversible hydrogen electrode , alloy , oxygen evolution , bifunctional catalyst , inorganic chemistry , electrode , nanotechnology , chemistry , electrochemistry , metallurgy , working electrode , organic chemistry , engineering
The pedestal of the rechargeable zinc–air battery (ZAB) is based on high‐performance bifunctional oxygen reduction/evolution reactions (ORR/OER) electrocatalysts. Herein, without any template or surfactant, in situ grown nitrogen‐doped carbon‐nanotube (NCNT)‐embedded with two phases of bimetal CoFe alloys and CoFe 2 O 4 spinel oxide are constructed, using inexpensive materials of glucose, urea, and cobalt/iron acetates by programing the pyrolysis temperature. The obtained catalyst with optimal cobalt/iron acetates mass ratio (1:1) denoted as CoFe–CoFe 2 O 4 –NCNT not only exceeds Pt–Ru/C in terms of ORR half‐wave potentials [(0.88 vs 0.84 V versus reversible hydrogen electrode (RHE)] and limiting current densities (6.40 vs 5.40 mA cm −2 ), but also manifests superior OER activity with the potentials of (1.58 vs 1.67 V versus RHE) at 10 mA cm −2 . Therefore, CoFe–CoFe 2 O 4 –NCNT exhibits a smaller Δ E value of (0.70 V versus RHE), surpassing that of Pt–Ru/C (0.85 V versus RHE) and shows excellent stability as well as outstanding methanol tolerance compared with the Pt–Ru/C commercial catalyst. In addition, CoFe–CoFe 2 O 4 –NCNT applied as a bifunctional air electrode in rechargeable ZAB displays a promising rechargeability performance with high‐discharge and low‐charge potentials and a relatively stable potential gap under 550 cycles, outperforming those of Pt–Ru/C.