A simple and low-cost method for the preparation of self-supported TiO2-WO3 ceramic heterojunction wafers

Neel M. Makwana*, Raul Quesada-Cabrera, Ivan P. Parkin, Paul F. McMillan, Andrew Mills, Jawwad A. Darr

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Robust, bilayer heterojunction photodiodes of TiO2-WO3 were prepared successfully by a simple, low-cost powder pressing technique followed by heat-treatment. Exclusive photoirradiation of the TiO2 side of the photodiode resulted in a rapid colour change (dark blue) on the WO3 surface as a result of reduction of W6+ to W5+ (confirmed by X-ray photoelectron spectroscopy). This colour was long lived and shown to be stable in a dry environment in air for several hours. A similar photoirradiation experiment in the presence of a mask showed that charge transfer across the heterojunction occurred approximately normal to the TiO2 surface, with little smearing out of the mask image. As a result of the highly efficient vectorial charge separation, the photodiodes showed a tremendous increase in photocatalytic activity for the degradation of stearic acid, compared to wafers of the respective individual materials when tested separately.

Original languageEnglish
Pages (from-to)17602-17608, Impact Factor: 7.4
Number of pages7
JournalJournal of Materials Chemistry A
Early online date10 Sep 2014
Publication statusPublished - 2014

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)


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