16 resultados para TRACE METALS
Filtro por publicador
- Aberystwyth University Repository - Reino Unido (2)
- Acceda, el repositorio institucional de la Universidad de Las Palmas de Gran Canaria. España (1)
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- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (16)
- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP) (9)
- Biblioteca Digital de Teses e Dissertações Eletrônicas da UERJ (5)
- Bioline International (1)
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- Boston University Digital Common (1)
- Brock University, Canada (10)
- CaltechTHESIS (11)
- Cambridge University Engineering Department Publications Database (45)
- CentAUR: Central Archive University of Reading - UK (10)
- Chinese Academy of Sciences Institutional Repositories Grid Portal (195)
- Cochin University of Science & Technology (CUSAT), India (30)
- CORA - Cork Open Research Archive - University College Cork - Ireland (1)
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- DI-fusion - The institutional repository of Université Libre de Bruxelles (7)
- Digital Commons - Michigan Tech (2)
- Digital Commons - Montana Tech (3)
- Digital Commons at Florida International University (5)
- DigitalCommons - The University of Maine Research (4)
- DigitalCommons@The Texas Medical Center (2)
- DRUM (Digital Repository at the University of Maryland) (3)
- Duke University (5)
- eResearch Archive - Queensland Department of Agriculture; Fisheries and Forestry (1)
- FAUBA DIGITAL: Repositorio institucional científico y académico de la Facultad de Agronomia de la Universidad de Buenos Aires (2)
- Gallica, Bibliotheque Numerique - Bibliothèque nationale de France (French National Library) (BnF), France (1)
- Greenwich Academic Literature Archive - UK (12)
- Helda - Digital Repository of University of Helsinki (9)
- Illinois Digital Environment for Access to Learning and Scholarship Repository (1)
- Indian Institute of Science - Bangalore - Índia (91)
- INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES (IPEN) - Repositório Digital da Produção Técnico Científica - BibliotecaTerezine Arantes Ferra (5)
- Instituto Politécnico do Porto, Portugal (6)
- Laboratório Nacional de Energia e Geologia - Portugal (1)
- Plymouth Marine Science Electronic Archive (PlyMSEA) (42)
- Portal de Revistas Científicas Complutenses - Espanha (2)
- Publishing Network for Geoscientific & Environmental Data (95)
- QSpace: Queen's University - Canada (1)
- QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast (115)
- Queensland University of Technology - ePrints Archive (72)
- Repositório Científico da Universidade de Évora - Portugal (1)
- Repositório Científico do Instituto Politécnico de Lisboa - Portugal (1)
- REPOSITORIO DIGITAL IMARPE - INSTITUTO DEL MAR DEL PERÚ, Peru (1)
- Repositório Institucional da Universidade de Aveiro - Portugal (9)
- Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho" (18)
- Royal College of Art Research Repository - Uninet Kingdom (1)
- RUN (Repositório da Universidade Nova de Lisboa) - FCT (Faculdade de Cienecias e Technologia), Universidade Nova de Lisboa (UNL), Portugal (1)
- SAPIENTIA - Universidade do Algarve - Portugal (3)
- Universidad de Alicante (1)
- Universidad Politécnica de Madrid (3)
- Universidade dos Açores - Portugal (1)
- Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP) (1)
- Universidade Federal do Pará (2)
- Universidade Federal do Rio Grande do Norte (UFRN) (4)
- Université de Lausanne, Switzerland (2)
- Université de Montréal, Canada (2)
- University of Michigan (8)
- University of Queensland eSpace - Australia (7)
- University of Washington (2)
Resumo:
The effect of trace quantities of ammonia on oxygen reduction reaction (ORR) on carbon-supported platinum catalysts in perchloric acid solutions is assessed using rotating ring disk electrode (RRDE) technique. The study demonstrates that ammonia has detrimental effects on ORR. The most significant effect takes place in the potential region above 0.7 V vs RHE. The effect is explained by the electrochemical oxidation of ammonia, which blocks Pt active sites and increases the formation of H2O2. This leads to losses in the disk currents and increments in the ring currents. The apparent losses in ORR currents may occur in two ways, namely, through the blocking of the active sites for ORR as well as by generating a small anodic current, which is believed to have a lower contribution. In addition, a detrimental effect of sodium cations in the potential range below 0.75 V vs RHE was demonstrated. This effect is most likely due to the co-adsorption of sodium cations and perchlorate anions on the Pt surface. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.