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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Influence of Aliovalent Substitutions on Oxygen Reduction on Tantalum Oxynitrides

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Author(s):
Pasqualeti, Anielli M. ; Padgett, Elliot ; Kuo, Ding-Yuan ; Muller, David A. ; Lima, Fabio H. B. ; Suntivich, Jin
Total Authors: 6
Document type: Journal article
Source: Journal of the Electrochemical Society; v. 164, n. 6, p. F645-F650, 2017.
Web of Science Citations: 1
Abstract

The development of active and stable oxygen reduction reaction (ORR) electrocatalysts using low-cost, abundant elements is of critical importance to the widespread adoption of proton-exchanged membrane fuel cells (PEMFCs). Tantalum-containing compounds, such as tantalum oxynitrides, can catalyze ORR in acid, with the degree of oxidation proposed to play a central role in controlling the ORR activity. Herein, we report the incorporation of aliovalent ions in tantalum oxynitrides (Ta-ON) and their effect on the ORR activity in acid. We synthesize Ta-ON by utilizing urea as the nitrogen source and use aliovalent (Ti4+) and isovalent (Nb5+) substitutions to evaluate the influence of the aliovalent substitution on the ORR activity. We found that an aliovalent Ti4+ substitution increases the ORR activity by 3x, which we attribute to improved electrical conductivity and increased ORR active sites. In comparison, isovalent Nb5+ substitution or carbon inclusion as oxycarbonitride did not positively affect the ORR activity. Our finding points to the important role of defects and conductivity in the Ta-based ORR electrocatalysts. (C) The Author(s) 2017. Published by ECS. All rights reserved. (AU)

FAPESP's process: 14/11923-5 - Metal sulfide and oxide nanostructures as electrocatalysts for hydrogen and oxygen electrodes
Grantee:Aniélli Martini Pasqualeti
Support type: Scholarships abroad - Research Internship - Doctorate
FAPESP's process: 16/13323-0 - Carbon dioxide and water electrochemistry: application in energy conversion and storage
Grantee:Fabio Henrique Barros de Lima
Support type: Regular Research Grants
FAPESP's process: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
Grantee:Edson Antonio Ticianelli
Support type: Research Projects - Thematic Grants
FAPESP's process: 13/03408-0 - Bifunctional electrocatalysts for reaction involved in regenerative electrochemical energy conversion devices that operate with H2/O2
Grantee:Aniélli Martini Pasqualeti
Support type: Scholarships in Brazil - Doctorate