The Different Roles of Water in Photocatalytic DeNOx Mechanisms on TiO2

A Basis for Engineering Nitrate Selectivity?

Lu Yang, Amer Hakki, Fazhou Wang, Donald E. Macphee

Research output: Contribution to journalArticle

8 Citations (Scopus)
5 Downloads (Pure)

Abstract

The nitrate selectivity of TiO2 has important consequences for its efficiency as a NOx depollution photocatalyst. Most emphasis is typically given to photocatalyst activity, a measure of the rate at which NOx concentrations are reduced, but a reduction in NOx concentration (mainly NO + NO2) is not necessarily a reduction in atmospheric NO2 concentration because the catalytic process itself generates NO2. With NO2 being considerably more toxic than NO, more emphasis on nitrate selectivity, a measure of the NOx conversion to nitrate, and how to maximise it, should be given in engineering photocatalytic systems for improved urban air quality. This study, on the importance of adsorbed water in the photocatalytic oxidation of NOx, has identified important correlations which differentiate the role that water plays in the oxidation of NO and NO2. This observation is significant and offers insights into controlling nitrate selectivity on TiO2 and the potential for increased effectiveness in environmental photocatalyst applications.
Original languageEnglish
Pages (from-to)17034-17041
Number of pages8
JournalACS Applied Materials & Interfaces
Volume9
Issue number20
Early online date5 May 2017
DOIs
Publication statusPublished - 24 May 2017

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Nitrates
Photocatalysts
Water
Oxidation
Poisons
Systems engineering
Air quality

Keywords

  • supported TiO2
  • synthesis conditions
  • adsorbed water
  • NOx
  • nitrate selectivity

Cite this

The Different Roles of Water in Photocatalytic DeNOx Mechanisms on TiO2 : A Basis for Engineering Nitrate Selectivity? / Yang, Lu; Hakki, Amer; Wang, Fazhou; Macphee, Donald E.

In: ACS Applied Materials & Interfaces, Vol. 9, No. 20, 24.05.2017, p. 17034-17041.

Research output: Contribution to journalArticle

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abstract = "The nitrate selectivity of TiO2 has important consequences for its efficiency as a NOx depollution photocatalyst. Most emphasis is typically given to photocatalyst activity, a measure of the rate at which NOx concentrations are reduced, but a reduction in NOx concentration (mainly NO + NO2) is not necessarily a reduction in atmospheric NO2 concentration because the catalytic process itself generates NO2. With NO2 being considerably more toxic than NO, more emphasis on nitrate selectivity, a measure of the NOx conversion to nitrate, and how to maximise it, should be given in engineering photocatalytic systems for improved urban air quality. This study, on the importance of adsorbed water in the photocatalytic oxidation of NOx, has identified important correlations which differentiate the role that water plays in the oxidation of NO and NO2. This observation is significant and offers insights into controlling nitrate selectivity on TiO2 and the potential for increased effectiveness in environmental photocatalyst applications.",
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AB - The nitrate selectivity of TiO2 has important consequences for its efficiency as a NOx depollution photocatalyst. Most emphasis is typically given to photocatalyst activity, a measure of the rate at which NOx concentrations are reduced, but a reduction in NOx concentration (mainly NO + NO2) is not necessarily a reduction in atmospheric NO2 concentration because the catalytic process itself generates NO2. With NO2 being considerably more toxic than NO, more emphasis on nitrate selectivity, a measure of the NOx conversion to nitrate, and how to maximise it, should be given in engineering photocatalytic systems for improved urban air quality. This study, on the importance of adsorbed water in the photocatalytic oxidation of NOx, has identified important correlations which differentiate the role that water plays in the oxidation of NO and NO2. This observation is significant and offers insights into controlling nitrate selectivity on TiO2 and the potential for increased effectiveness in environmental photocatalyst applications.

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