Fabrication of porous tungsten oxide via anodizing in an ammonium nitrate/ethylene glycol/water mixture for visible light-driven photocatalyst

Tatsuya Kikuchi, Jun Kawashima, Shungo Natsui, Ryosuke O. Suzuki

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Fabrication of a nanoporous tungsten oxide film via anodizing of tungsten in an ammonium nitrate (NH 4 NO 3 )/ethylene glycol (EG)/water (H 2 O) mixture is reported for use as a visible light-driven photocatalyst. Anodizing of tungsten in a 1.0 M NH 4 NO 3 /EG solution containing less than 0.1 vol% H 2 O resulted in active dissolution of the tungsten substrate. As the H 2 O concentration increased to more than 25 vol%, a thin barrier oxide film was formed on the tungsten substrate. A thick porous tungsten oxide with numerous nanopores measuring several tens of nanometer in diameter was fabricated via anodizing at a moderate H 2 O concentration of 1.0 vol%. The porous oxide consisted of a double-layered structure with an outer porous layer and an inner dense layer, and the outer porous layer became thinner as the NH 4 NO 3 concentration decreased. A uniform porous oxide film from the top surface to the bottom interface was fabricated via anodizing at 20 V in a 0.02 M NH 4 NO 3 /EG solution containing 1.0 vol% H 2 O at 313 K. The porous tungsten oxide exhibited visible light-driven photocatalytic activity for the photocatalytic decomposition of methylene blue.

Original languageEnglish
Pages (from-to)130-137
Number of pages8
JournalApplied Surface Science
Volume422
DOIs
Publication statusPublished - 2017 Nov 15
Externally publishedYes

Keywords

  • Anodizing
  • Photocatalyst
  • Porous oxide
  • Tungsten
  • Visible light

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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