Photocatalytic WO3/TiO2 nanowires

WO3 polymorphs influencing the atomic layer deposition of TiO2

Dávidné Nagy, Tamás Firkala, Eszter Drotár, A. Szegedi, K. László, Imre Miklós Szilágyi

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

50-70 nm hexagonal (h-) and 70-90 nm monoclinic (m-) WO3 nanoparticles (NPs) were prepared by controlled annealing of (NH4)xWO3 in air at 470 and 600 °C, respectively. In addition, 5-10 nm thick and several micrometer long h-WO3 nanowires (NWs) were obtained by microwave hydrothermal synthesis at 160 °C with Na2WO4, HCl and (NH4)2SO4 as starting materials. TiO2 was deposited on h-WO3 NWs by atomic layer deposition (ALD) at 300 °C using Ti(iOPr)4 and H2O as precursors. The as-prepared materials were studied by TG/DTA-MS, XRD, Raman, SEM-EDX, TEM, ellipsometry, UV-Vis, and their photocatalytic activity was also tested by the photodecomposition of aqueous methyl orange. Our study is the first evidence of diverse ALD nucleation on various WO3 polymorphs, since on h-WO3 NWs TiO2 nucleated only as particles, whereas on m-WO3 conformal TiO2 film was formed, explained by the different surface OH coverage of h- and m-WO3. The h-WO3 NWs had significantly higher photocatalytic activity compared to h-WO3 NPs, and similar performance as m-WO3 NPs. By adding TiO2 to h-WO3 NWs by ALD method, the photocatalytic performance increased by 65%, showing clearly the uniqueness of ALD to obtain superior oxide composite photocatalysts.

Original languageEnglish
Pages (from-to)95369-95377
Number of pages9
JournalRSC Advances
Volume6
Issue number98
DOIs
Publication statusPublished - 2016

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Atomic layer deposition
Polymorphism
Nanowires
Nanoparticles
Hydrothermal synthesis
Ellipsometry
Photocatalysts
Differential thermal analysis
Oxides
Energy dispersive spectroscopy
Nucleation
Microwaves
Annealing
Transmission electron microscopy
Scanning electron microscopy
Composite materials
Air

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Cite this

Photocatalytic WO3/TiO2 nanowires : WO3 polymorphs influencing the atomic layer deposition of TiO2. / Nagy, Dávidné; Firkala, Tamás; Drotár, Eszter; Szegedi, A.; László, K.; Szilágyi, Imre Miklós.

In: RSC Advances, Vol. 6, No. 98, 2016, p. 95369-95377.

Research output: Contribution to journalArticle

Nagy, Dávidné ; Firkala, Tamás ; Drotár, Eszter ; Szegedi, A. ; László, K. ; Szilágyi, Imre Miklós. / Photocatalytic WO3/TiO2 nanowires : WO3 polymorphs influencing the atomic layer deposition of TiO2. In: RSC Advances. 2016 ; Vol. 6, No. 98. pp. 95369-95377.
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