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Rational Design of Spinel Cobalt Vanadate Oxide Co 2 VO 4 for Superior Electrocatalysis
Author(s) -
Mu Chuan,
Mao Jing,
Guo Jiaxin,
Guo Qianjin,
Li Zhiqing,
Qin Wenjing,
Hu Zhenpeng,
Davey Kenneth,
Ling Tao,
Qiao ShiZhang
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201907168
Subject(s) - cobalt , materials science , spinel , cobalt oxide , electrocatalyst , oxide , vanadium oxide , catalysis , inorganic chemistry , electrochemical energy conversion , electrochemistry , chemical engineering , chemistry , electrode , metallurgy , biochemistry , engineering
Electrochemical energy devices, such as fuel cells and metal–air batteries, convert chemical energy directly into electricity without adverse environmental impact. Attractive alternatives to expensive noble metals used in these renewable energy technologies are earth‐abundant transition metal oxides. However, they are often limited by catalytic and conductive capabilities. Here reported is a spinel oxide, Co 2 VO 4 , by marrying metallic vanadium atomic chains with electroactive cobalt cations for superior oxygen reduction reaction (ORR)—a key process for fuel cells, metal–air batteries, etc. The experimental and simulated electron energy‐loss spectroscopy analyses reveal that Co 2+ cations at the octahedral sites take the low spin state with one e g electron ( t 2 g 6 e g 1 ) , favoring advantageous ORR energetics. Measurement of actual electrical conductivity confirms that Co 2 VO 4 has several orders of magnitude increase when compared with benchmark cobalt oxides. As a result, a zinc–air battery with new spinel cobalt vanadate oxide as the ORR catalyst shows excellent performance, together with a record‐high discharge peak power density of 380 mW cm −2 . Crucially, this is superior to state‐of‐the‐art Pt/C‐based device and is greatest among zinc–air batteries assembled with metal, metal oxide, and carbon catalysts. The findings present a new design strategy for highly active and conductive oxide materials for a wide range of electrocatalytic applications, including ORR, oxygen evolution, and hydrogen evolution reactions.