1 resultado para Influence of the temperature
em Cochin University of Science
Filtro por publicador
- KUPS-Datenbank - Universität zu Köln - Kölner UniversitätsPublikationsServer (1)
- Acceda, el repositorio institucional de la Universidad de Las Palmas de Gran Canaria. España (3)
- AMS Tesi di Dottorato - Alm@DL - Università di Bologna (1)
- Aquatic Commons (17)
- ArchiMeD - Elektronische Publikationen der Universität Mainz - Alemanha (2)
- Archimer: Archive de l'Institut francais de recherche pour l'exploitation de la mer (2)
- Archive of European Integration (7)
- Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco (7)
- Aston University Research Archive (19)
- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (37)
- Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP) (9)
- BORIS: Bern Open Repository and Information System - Berna - Suiça (41)
- Brock University, Canada (5)
- Bulgarian Digital Mathematics Library at IMI-BAS (2)
- CaltechTHESIS (1)
- Cambridge University Engineering Department Publications Database (35)
- CentAUR: Central Archive University of Reading - UK (38)
- Central European University - Research Support Scheme (1)
- Chinese Academy of Sciences Institutional Repositories Grid Portal (114)
- Cochin University of Science & Technology (CUSAT), India (1)
- Coffee Science - Universidade Federal de Lavras (1)
- Comissão Econômica para a América Latina e o Caribe (CEPAL) (4)
- CORA - Cork Open Research Archive - University College Cork - Ireland (6)
- Corvinus Research Archive - The institutional repository for the Corvinus University of Budapest (1)
- Deakin Research Online - Australia (29)
- DI-fusion - The institutional repository of Université Libre de Bruxelles (2)
- Digital Commons at Florida International University (3)
- Digital Knowledge Repository of Central Drug Research Institute (1)
- DigitalCommons@The Texas Medical Center (4)
- Diposit Digital de la UB - Universidade de Barcelona (3)
- Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland (1)
- DRUM (Digital Repository at the University of Maryland) (3)
- Duke University (1)
- Ecology and Society (1)
- eResearch Archive - Queensland Department of Agriculture; Fisheries and Forestry (3)
- FUNDAJ - Fundação Joaquim Nabuco (1)
- Glasgow Theses Service (1)
- Greenwich Academic Literature Archive - UK (2)
- Helda - Digital Repository of University of Helsinki (3)
- Hospitais da Universidade de Coimbra (1)
- Indian Institute of Science - Bangalore - Índia (66)
- Institutional Repository of Leibniz University Hannover (2)
- INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES (IPEN) - Repositório Digital da Produção Técnico Científica - BibliotecaTerezine Arantes Ferra (3)
- Instituto Politécnico de Viseu (1)
- Instituto Politécnico do Porto, Portugal (4)
- Memorial University Research Repository (3)
- Ministerio de Cultura, Spain (3)
- National Center for Biotechnology Information - NCBI (2)
- Nottingham eTheses (1)
- Plymouth Marine Science Electronic Archive (PlyMSEA) (8)
- Portal de Revistas Científicas Complutenses - Espanha (3)
- Publishing Network for Geoscientific & Environmental Data (4)
- QSpace: Queen's University - Canada (1)
- QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast (58)
- Queensland University of Technology - ePrints Archive (46)
- Repositório Alice (Acesso Livre à Informação Científica da Embrapa / Repository Open Access to Scientific Information from Embrapa) (1)
- Repositório Científico da Universidade de Évora - Portugal (2)
- Repositório Científico do Instituto Politécnico de Lisboa - Portugal (2)
- Repositório digital da Fundação Getúlio Vargas - FGV (4)
- Repositório Institucional da Universidade de Aveiro - Portugal (1)
- Repositório Institucional da Universidade Federal do Rio Grande - FURG (1)
- Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho" (207)
- Repositorio Institucional Universidad de Medellín (1)
- SAPIENTIA - Universidade do Algarve - Portugal (2)
- Scielo España (1)
- Universidad de Alicante (11)
- Universidad del Rosario, Colombia (2)
- Universidad Politécnica de Madrid (46)
- Universidade Complutense de Madrid (2)
- Universidade do Algarve (1)
- Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP) (2)
- Universidade Federal do Pará (5)
- Universidade Federal do Rio Grande do Norte (UFRN) (1)
- Universidade Técnica de Lisboa (1)
- Universitat de Girona, Spain (1)
- Universitätsbibliothek Kassel, Universität Kassel, Germany (4)
- Université de Montréal, Canada (1)
- University of Michigan (25)
- University of Queensland eSpace - Australia (12)
- WestminsterResearch - UK (1)
- Worcester Research and Publications - Worcester Research and Publications - UK (1)
Resumo:
A series of vanadium-niobium oxide catalysts in which the vanadia content varies between 0.3 and 18mol%was prepared by coprecipitation. These catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering (LEIS), and by catalytic testing in the oxidative dehydrogenation reaction of propane. The results of the surface analysis by XPS and LEIS are compared. It is concluded that the active site on the catalyst surface contains 2.0 ± 0.3 vanadium atoms on average. This can be understood byassuming the existenceof two or three different sites:isolated vanadium atoms, pairs of vanadium atoms, or ensembles of three vanadium atoms. At higher vanadium concentration more vanadium clusters with a higher activity are at the surface.LEIS revealed that as the vanadium concentration in the catalyst increases, vanadium replaces niobium at the surface. At vanadium concentrations above 8 mol%, new phases such as P-(Nb, V)20S which are less active because vanadium is present in isolated sites are formed, while the vanadium surface concentration shows a slight decrease