Improved high temperature stability of anatase TiO2 photocatalysts by N, F, P co-doping

Rachel Fagan, Declan E. McCormack*, Steve Hinder, Suresh C. Pillai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Among the three commonly occurring phases (anatase, rutile, and brookite) of TiO2, the anatase form is reported to be the best photocatalyst due to the improved charge-carrier mobility and the greater number of surface hydroxyl groups. The anatase to rutile transition in titania photocatalysts usually occurs at a temperature between 500 °C to 700 °C. Development of a high temperature stable (above 1000 °C) anatase phase is important for various environmental applications (e.g. self-cleaning ceramic tiles, anti-microbial sanitary wares, etc.). In this study, the use of ammonium hexafluorophosphate as a single source dopant (method A) and urea, trifluoroacetic acid and phosphoric acid as multiple sources (method B) was undertaken to improving its high temperature stability. Method A was seen to produce a more stable anatase phase, with 68% anatase present at 1100 °C, compared to method B which showed 100% rutile at 900 °C. Kinetic analysis shows a marked increase in the photocatalytic degradation of a model dye using materials calcined at 1100 °C for method A (0.042 min-1) compared to that for method B (0.005 min-1) and the commercial photocatalyst Evonik-Degussa AEROXIDE® (0.031 min-1) at 1100 °C. XPS results showed that, the only dopant detected at high temperatures is phosphorus in its P5+ form. The incorporation of phosphorus has proved to be an effective method in stabilising the anatase phase at high temperature. The current investigation also showed that a single source precursor is more favourable to obtain high temperature stable anatase phase photocatalysts.

Original languageEnglish
Pages (from-to)44-53
Number of pages10
JournalMaterials and Design
Volume96
DOIs
Publication statusPublished - Apr 15 2016

Keywords

  • Anatase
  • Photocatalysis
  • Rutile
  • TiO

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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