Effect of controlled periodic-based illumination on the photonic efficiency of photocatalytic degradation of methyl orange

Oluwatosin I. Tokode, Radhakrishna Prabhu, Linda A. Lawton, Peter K J Robertson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)
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The use of controlled periodic illumination with UV LEDs for enhancing photonic efficiency of photocatalytic decomposition processes in water has been investigated using methyl orange as a model compound. The impact of the length of light and dark time periods (T ON/T OFF times) on photodegradation and photonic efficiency using a UV LED-illuminated photoreactor has been studied. The results have shown an inverse dependency of the photonic efficiency on duty cycle and a very little effect on T ON or T OFF time periods, indicating no effect of rate-limiting steps through mass diffusion or adsorption/desorption in the reaction. For this reactor, the photonic efficiency under controlled periodic illumination (CPI) matches to that of continuous illumination, for the same average UV light intensities. Furthermore, under CPI conditions, the photonic efficiency is inversely related to the average UV light intensity in the reactor, in the millisecond time regime. This is the first study that has investigated the effect of controlled periodic illumination using ultra band gap UV LED light sources in the photocatalytic destruction of dye compounds using titanium dioxide. The results not only enhance the understanding of the effect of periodic illumination on photocatalytic processes but also provide a greater insight to the potential of these light sources in photocatalytic reactions. 

Original languageEnglish
Pages (from-to)138-142
Number of pages5
JournalJournal of Catalysis
Early online date21 Apr 2012
Publication statusPublished - Jun 2012


  • Controlled periodic illumination
  • Photocatalysis
  • Photonic efficiency
  • Photoreactor
  • Titanium dioxide
  • UV LED

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry


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