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Metal-substrate-supported tungsten-oxide nanoarrays via porous-alumina-assisted anodization: from nanocolumns to nanocapsules and nanotubes

  • Datos identificativos

    Identificador: imarina:6388782
    Autores:
    Mozalev, AlexanderBendova, MariaGispert-Guirado, FrancescPytlicek, ZdenekLlobet, Eduard
    Resumen:
    © The Royal Society of Chemistry 2016. An array of highly aligned tungsten-oxide (TO) nanorods, ∼80 nm wide, up to 900 nm long, spatially separated at their bottoms by tungsten metal on a substrate is synthesized via the self-localized anodization of aluminum followed by the porous-alumina-assisted re-anodization of tungsten in a sputter-deposited Al/W bilayer. Moreover, the pore-directed TO nanocapsules may grow, which can be electrochemically top-opened in alumina nanopores and transformed to TO nanotubes, representing unique architectures built up on tungsten substrates to date. The as-grown nanorods are composed of amorphous WO3mixed with minor amounts of WO2and Al2O3in the outer layer and oxide-hydroxide compound (WO3·nH2O) with aluminum tungstate (2Al2O3·5WO3), mainly present inside the rods. Once the growing oxide fills up the pores, it comes out as an array of exotic protuberances of highly hydrated TO, with no analogues among the other valve-metal oxides. Vacuum or air annealing at 550 °C increases the portion of non-stoichiometric oxides 'doped' with OH-groups and gives monoclinic WO2.9or a mixture of WO3and WO2.9nanocrystalline phases, respectively. The nanorods show n-type semiconductor behavior when examined by Mott-Schottky analysis, with a high carrier density of 7 × 1019or 3 × 1019cm-3for the air- or vacuum-annealed samples, associated with a charge depletion layer of about 8 or 10 nm, respectively. A model for the growth of the metal-substrate-separated TO nanocapsules and tubes is proposed and experimentally justified. The findings suggest that the new TO nanoarrays with well-defined nano-channels for carriers may form the basic elements for photoanodes or emerging 3-D micro- and nano-sensors.
  • Otros:

    Autor según el artículo: Mozalev, Alexander; Bendova, Maria; Gispert-Guirado, Francesc; Pytlicek, Zdenek; Llobet, Eduard
    Departamento: Enginyeria Electrònica, Elèctrica i Automàtica
    Autor/es de la URV: Gispert Guirado, Francesc / GUIRADO PAGÉS, FRANCISCO / Llobet Valero, Eduard
    Palabras clave: Oxides Nanocapsules Alumina
    Resumen: © The Royal Society of Chemistry 2016. An array of highly aligned tungsten-oxide (TO) nanorods, ∼80 nm wide, up to 900 nm long, spatially separated at their bottoms by tungsten metal on a substrate is synthesized via the self-localized anodization of aluminum followed by the porous-alumina-assisted re-anodization of tungsten in a sputter-deposited Al/W bilayer. Moreover, the pore-directed TO nanocapsules may grow, which can be electrochemically top-opened in alumina nanopores and transformed to TO nanotubes, representing unique architectures built up on tungsten substrates to date. The as-grown nanorods are composed of amorphous WO3mixed with minor amounts of WO2and Al2O3in the outer layer and oxide-hydroxide compound (WO3·nH2O) with aluminum tungstate (2Al2O3·5WO3), mainly present inside the rods. Once the growing oxide fills up the pores, it comes out as an array of exotic protuberances of highly hydrated TO, with no analogues among the other valve-metal oxides. Vacuum or air annealing at 550 °C increases the portion of non-stoichiometric oxides 'doped' with OH-groups and gives monoclinic WO2.9or a mixture of WO3and WO2.9nanocrystalline phases, respectively. The nanorods show n-type semiconductor behavior when examined by Mott-Schottky analysis, with a high carrier density of 7 × 1019or 3 × 1019cm-3for the air- or vacuum-annealed samples, associated with a charge depletion layer of about 8 or 10 nm, respectively. A model for the growth of the metal-substrate-separated TO nanocapsules and tubes is proposed and experimentally justified. The findings suggest that the new TO nanoarrays with well-defined nano-channels for carriers may form the basic elements for photoanodes or emerging 3-D micro- and nano-sensors.
    Áreas temáticas: Renewable energy, sustainability and the environment Química Odontología Medicina i Materials science, multidisciplinary Materials science (miscellaneous) Materials science (all) Materials science Materials chemistry Materiais Interdisciplinar General materials science General chemistry Farmacia Engenharias iv Engenharias ii Energy & fuels Ciências biológicas ii Ciências biológicas i Ciências agrárias i Chemistry, physical Chemistry (miscellaneous) Chemistry (all) Biotecnología Biodiversidade Astronomia / física
    Acceso a la licencia de uso: https://creativecommons.org/licenses/by/3.0/es/
    ISSN: 0959-9428
    Direcció de correo del autor: eduard.llobet@urv.cat
    Identificador del autor: 0000-0001-6164-4342
    Página final: 8232
    Fecha de alta del registro: 2024-10-12
    Volumen de revista: 4
    Versión del articulo depositado: info:eu-repo/semantics/publishedVersion
    Enlace a la fuente original: https://pubs.rsc.org/en/content/articlelanding/2016/TA/C6TA02027E#!divAbstract
    URL Documento de licencia: https://repositori.urv.cat/ca/proteccio-de-dades/
    Referencia al articulo segun fuente origial: Journal Of Materials Chemistry a. 4 (21): 8219-8232
    Referencia de l'ítem segons les normes APA: Mozalev, Alexander; Bendova, Maria; Gispert-Guirado, Francesc; Pytlicek, Zdenek; Llobet, Eduard (2016). Metal-substrate-supported tungsten-oxide nanoarrays via porous-alumina-assisted anodization: from nanocolumns to nanocapsules and nanotubes. Journal Of Materials Chemistry a, 4(21), 8219-8232. DOI: 10.1039/c6ta02027e
    DOI del artículo: 10.1039/c6ta02027e
    Entidad: Universitat Rovira i Virgili
    Año de publicación de la revista: 2016
    Página inicial: 8219
    Tipo de publicación: Journal Publications
  • Palabras clave:

    Chemistry (Miscellaneous),Chemistry, Physical,Energy & Fuels,Materials Chemistry,Materials Science,Materials Science (Miscellaneous),Materials Science, Multidisciplinary,Renewable Energy, Sustainability and the Environment
    Oxides
    Nanocapsules
    Alumina
    Renewable energy, sustainability and the environment
    Química
    Odontología
    Medicina i
    Materials science, multidisciplinary
    Materials science (miscellaneous)
    Materials science (all)
    Materials science
    Materials chemistry
    Materiais
    Interdisciplinar
    General materials science
    General chemistry
    Farmacia
    Engenharias iv
    Engenharias ii
    Energy & fuels
    Ciências biológicas ii
    Ciências biológicas i
    Ciências agrárias i
    Chemistry, physical
    Chemistry (miscellaneous)
    Chemistry (all)
    Biotecnología
    Biodiversidade
    Astronomia / física
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