Photocatalytic activity and charge carrier dynamics of TiO2 powders with a binary particle size distribution

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dc.identifier.uri Sieland, Fabian Schneider, Jenny Bahnemann, Detlef W. 2018-04-27T12:18:18Z 2018-04-27T12:18:18Z 2018
dc.identifier.citation Sieland, F.; Schneider, J.; Bahnemann, D.W.: Photocatalytic activity and charge carrier dynamics of TiO2 powders with a binary particle size distribution. In: Physical Chemistry Chemical Physics 20 (2018), Nr. 12, S. 8119-8132. DOI:
dc.description.abstract The effects of the particle size distribution on the charge carrier dynamics and the photocatalytic activity of mixed titanium dioxide (TiO2) powder samples were investigated in this work. Instead of the synthesis of the small semiconductor particles, the binary particle size distributions of the powders were obtained by mixing commercially available TiO2 powders with different particle sizes. The pure anatase samples (average diameters: 7, 20, and 125 nm, respectively) were created via ultrasound treatment and discreet drying. The photocatalytic activity of the powder samples was assessed by the degradation of nitric oxide (NO) and acetaldehyde in the gas phase. Furthermore, the charge carrier kinetics was determined using transient absorption spectroscopy following pulsed laser excitation. Importantly, a recently published model based on fractal dimensions was used to fit the transient signals of the photo generated charge carriers in the TiO2 powder samples. The effects of the particle size on the acetaldehyde degradation could be explained by the formation of agglomerates, which reduce the available surface area of smaller particles. The fast oxidation of acetaldehyde on the surface of TiO2 by direct hole transfer was further independent of the observed charge carrier lifetimes on the microsecond time scale. The photocatalytic NO degradation, on the other hand, increased for samples containing larger amounts of small particles. The corresponding photonic efficiencies correlated well with the charge carrier lifetimes determined by the time-resolved studies. Hence, it was concluded that a long charge carrier lifetime generally leads to higher fractional conversions of NO. The employed fractal fit function was proved to be beneficial for the kinetic analysis of charge carrier recombination in TiO2, in direct comparison with a second order fit function. © 2018 the Owner Societies. eng
dc.language.iso eng
dc.publisher Cambridge : Royal Society of Chemistry
dc.relation.ispartofseries Physical Chemistry Chemical Physics 20 (2018), Nr. 12
dc.rights CC BY-NC 3.0 Unported
dc.subject carrier dynamics eng
dc.subject photocatalytic activity eng
dc.subject TiO2 eng
dc.subject titanium dioxide eng
dc.subject nitric oxide eng
dc.subject NO eng
dc.subject.ddc 540 | Chemie ger
dc.title Photocatalytic activity and charge carrier dynamics of TiO2 powders with a binary particle size distribution
dc.type article
dc.type Text
dc.relation.issn 1463-9076
dc.bibliographicCitation.issue 12
dc.bibliographicCitation.volume 20
dc.bibliographicCitation.firstPage 8119
dc.bibliographicCitation.lastPage 8132
dc.description.version publishedVersion
tib.accessRights frei zug�nglich

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