Rational Design of Spinel Cobalt Vanadate Oxide Co2 VO4 for Superior Electrocatalysis
© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
| Publié dans: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 32(2020), 10 vom: 16. März, Seite e1907168 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2020
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| Accès à la collection: | Advanced materials (Deerfield Beach, Fla.) |
| Sujets: | Journal Article fuel cells oxygen reduction spinel cobalt vanadate oxide |
| Résumé: | © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 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, Co2 VO4 , 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 Co2+ cations at the octahedral sites take the low spin state with one eg electron ( t 2 g 6 e g 1 ) , favoring advantageous ORR energetics. Measurement of actual electrical conductivity confirms that Co2 VO4 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 |
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| Description: | Date Revised 30.09.2020 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.201907168 |