title: Photocatalytic performance of freestanding tetragonal zirconia nanotubes formed in H2O2/NH4F/ethylene glycol electrolyte by anodisation of zirconium.
abstract: ZrO2nanotubes (ZrNTs) were produced by anodisation of zirconium foil in H2O2/NH4F/ethylene glycol electrolyte. The as-anodised foils were then soaked in the anodising electrolyte for 12 h. Soaking weakens the adherence of the anodic layer from the substrate resulting in freestanding ZrNTs (FS-ZrNTs). Moreover, the presence of H2O2in the electrolyte also aids in weakening the adhesion of the film from the foil, as foil anodised in electrolyte without H2O2has good film adherence. The as-anodised FS-ZrNTs film was amorphous and crystallised to predominantly tetragonal phase upon annealing at >300 °C. Annealing must, however, be done at <500 °C to avoid monoclinic ZrO2formation and nanotubes disintegration. FS-ZrNTs annealed at 450 °C exhibited the highest photocatalytic ability to degrade methyl orange (MO), whereby 82% MO degradation was observed after 5 h, whereas FS-ZrNTs with a mixture of monoclinic and tetragonal degraded 70% of MO after 5 h.
authors.affiliation: Green Electronics nanoMaterials Group, Science and Engineering of Nanomaterials Team, School of Materials and Mineral Resources, Universiti Sains Malaysia, Penang 14300, Malaysia.
authors.forename: Monna
authors.initials: M
authors.lastname: Rozana
authors.forename: Nurul Izza
authors.initials: NI
authors.lastname: Soaid
authors.forename: Tan Wai
authors.initials: TW
authors.lastname: Kian
authors.forename: Go
authors.initials: G
authors.lastname: Kawamura
authors.forename: Atsunori
authors.initials: A
authors.lastname: Matsuda
authors.forename: Zainovia
authors.initials: Z
authors.lastname: Lockman