title: Growth, Structure, and Photocatalytic Properties of Hierarchical V₂O₅-TiO₂ Nanotube Arrays Obtained from the One-step Anodic Oxidation of Ti-V Alloys.
abstract: V₂O₅-TiO₂ mixed oxide nanotube (NT) layers were successfully prepared via the one-step anodization of Ti-V alloys. The obtained samples were characterized by scanning electron microscopy (SEM), UV-Vis absorption, photoluminescence spectroscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (DRX), and micro-Raman spectroscopy. The effect of the applied voltage (30-50 V), vanadium content (5-15 wt %) in the alloy, and water content (2-10 vol %) in an ethylene glycol-based electrolyte was studied systematically to determine their influence on the morphology, and for the first-time, on the photocatalytic properties of these nanomaterials. The morphology of the samples varied from sponge-like to highly-organized nanotubular structures. The vanadium content in the alloy was found to have the highest influence on the morphology and the sample with the lowest vanadium content (5 wt %) exhibited the best auto-alignment and self-organization (length = 1 μm, diameter = 86 nm and wall thickness = 11 nm). Additionally, a probable growth mechanism of V₂O₅-TiO₂ nanotubes (NTs) over the Ti-V alloys was presented. Toluene, in the gas phase, was effectively removed through photodegradation under visible light (LEDs, λmax= 465 nm) in the presence of the modified TiO₂ nanostructures. The highest degradation value was 35% after 60 min of irradiation. V₂O₅ species were ascribed as the main structures responsible for the generation of photoactive e-and h⁺ under Vis light and a possible excitation mechanism was proposed.
authors.affiliation: Facultad de Ingeniería Química y Agroindustria, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, P.O. Box 17-01-2759, Quito 170525, Ecuador. ma.cristina.nevarez@gmail.com.|Centro de Investigación y Control Ambiental "CICAM", Departamento de Ingeniería Civil y Ambiental, Facultad de Ingeniería Civil y Ambiental, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, P.O. Box 17-01-2759, Quito 170525, Ecuador. ma.cristina.nevarez@gmail.com.
authors.forename: María C
authors.initials: MC
authors.lastname: Nevárez-Martínez
authors.affiliation: Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk 80-308, Poland. pawel.mazierski@phdstud.ug.edu.pl.
authors.forename: Paweł
authors.initials: P
authors.lastname: Mazierski
authors.affiliation: Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk 80-308, Poland. marek.kobylanski@phdstud.ug.edu.pl.
authors.forename: Marek P
authors.initials: MP
authors.lastname: Kobylański
authors.affiliation: Faculty of Chemistry, Nicolaus Copernicus University, Torun 87-100, Poland. gina@chem.umk.pl.
authors.forename: Grażyna
authors.initials: G
authors.lastname: Szczepańska
authors.affiliation: Faculty of Chemistry, Nicolaus Copernicus University, Torun 87-100, Poland. grazyna.szczepanska@umk.pl.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Trykowski
authors.affiliation: Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk 80-308, Poland. anna.malankowska@ug.edu.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Malankowska
authors.affiliation: Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk 80-308, Poland. magda.kozak@ug.edu.pl.
authors.forename: Magda
authors.initials: M
authors.lastname: Kozak
authors.affiliation: Centro de Investigación y Control Ambiental "CICAM", Departamento de Ingeniería Civil y Ambiental, Facultad de Ingeniería Civil y Ambiental, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, P.O. Box 17-01-2759, Quito 170525, Ecuador. patricio.espinoza@epn.edu.ec.
authors.forename: Patricio J
authors.initials: PJ
authors.lastname: Espinoza-Montero
authors.affiliation: Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Gdansk 80-308, Poland. adriana.zaleska@ug.edu.pl.
authors.forename: Adriana
authors.initials: A
authors.lastname: Zaleska-Medynska
mesh_terms: D000497:Alloys; D002384:Catalysis; D004566:Electrodes; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D010782:Photolysis; D013057:Spectrum Analysis; D014025:Titanium / Q000737:chemistry*; D017968:Vanadium Compounds / Q000737:chemistry*
chemical_list: D000497:Alloys; D017968:Vanadium Compounds; C009495:titanium dioxide; C066075:vanadium pentoxide; D014025:Titanium
keywords: V2O5-TiO2 nanotubes; air treatment; alloys; toluene degradation; visible-light-driven photocatalysis