Titel
Defect-Engineered Hydroxylated Mesoporous Spinel Oxides as Bifunctional Electrocatalysts for Oxygen Reduction and Evolution Reactions
Autor*in
Jakub Čížek
Department of Low-Temperature Physics, Faculty of Mathematics and Physics, Charles University
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Abstract
In this work, defect-rich ordered mesoporous spinel oxides, including CoCo2O4, NiCo2O4, and ZnCo2O4, were developed as bifunctional electrocatalysts toward oxygen reduction and evolution reactions (ORR and OER, respectively). The materials are synthesized via nanocasting and modified by chemical treatment with 0.1 M NaBH4 solution to enhance the defect concentration. The synthesized samples have metal and oxygen divacancies (VCo + VO) as the primary defect sites, as indicated by positron annihilation lifetime spectroscopy (PALS). Cation substitution in the spinel structure induces a higher number of oxygen vacancies. The increased number of surface defects and the synergistic effect between two incorporated metals provide a high activity in both the OER and ORR in the case of NiCo2O4 and ZnCo2O4. Especially, ZnCo2O4 exhibits the highest OER/ORR activity. The defect engineering with 0.1 M NaBH4 solution results in a metal-hydroxylated surface (M-OH) and enhanced the catalytic activity for the post-treated metal oxides in the ORR and OER. This fundamental investigation of the defective structure of the mixed metal oxides offers some useful insights into further development of highly active electrocatalysts through defect engineering methods.
Stichwort
mesoporous materialsnanocastingmixed metal spinel oxidesvacancy defectsbifunctional electrocatalystORROERPALS
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
ACS Applied Materials & Interfaces
Band
14
Ausgabe
20
ISSN
1944-8244
Erscheinungsdatum
2022
Seitenanfang
23307
Seitenende
23321
Publication
American Chemical Society (ACS)
Erscheinungsdatum
2022
Zugänglichkeit
Rechte
Rechteangabe
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