Effects of metal nanoparticles deposition on the photocatalytic oxidation of ammonia in TiO2 aqueous suspensions

Marco Altomare, Elena Selli*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

65 Citations (Scopus)

Abstract

TiO2 powders modified through the deposition of surfactant-stabilized preformed metal (Pt, Pd, Au and Ag) nanoparticles (NPs) were tested as photocatalysts for batch ammonia photo-oxidation in aqueous suspension, under UVA irradiation. NH3 conversion and the selectivity toward mildly oxidized N2 and highly oxidized nitrite and nitrate anions were monitored during the runs, in order to study the effects of noble metal NPs deposition on the reaction mechanism. This involves parallel and consecutive paths, also depending on the type of metal deposited on TiO2, as also highlighted by the nitrite photo-oxidation tests performed in the present study. Metal NPs acted as electron traps ensuring better separation of the photoproduced charge couples and consequently higher rates of hole-mediated oxidation reactions. Apart from Au/TiO2, the metal-modified powders exhibited higher photoactivity with respect to that of naked titania, with Ag/TiO2 being the best performing photocatalyst in terms of ammonia conversion. On the other hand, Pd NPs on TiO2 ensured a considerable increase of the selectivity toward N2 and may thus be considered the best co-catalysts of TiO2 for environmentally friendly photocatalytic NH3 abatement.
Original languageEnglish
Pages (from-to)127-133
Number of pages7
JournalCatalysis today
Volume209
Early online date10 Jan 2013
DOIs
Publication statusPublished - 15 Jun 2013
Externally publishedYes

Keywords

  • n/a OA procedure

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