Charge carrier dynamics and photocatalytic behavior of TiO2 nanopowders submitted to hydrothermal or conventional heat treatment

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dc.identifier.uri Patrocinio, Antonio Otavio T. Schneider, J. Franca, M.D. Santos, Lidiaine M. Caixeta, B.P. Machado, Antonio Eduardo H. Bahnemann, Detlef W. 2015-12-03T10:13:28Z 2016-08-12T22:05:26Z 2015-08-12
dc.identifier.citation Patrocinio, A. O. T.; Schneider, J.; Franca, M. D.; Santos, L. M.; Caixeta, B. P.; Machado, A. E. H.; Bahnemann, D. W.: Charge carrier dynamics and photocatalytic behavior of TiO2 nanopowders submitted to hydrothermal or conventional heat treatment. In: RSC Advances 5 (2015), Nr. 86, S. 70536-70545. DOI:
dc.description.abstract The sol–gel technique followed by conventional (TiO2-1) and hydrothermal (TiO2-2) thermal treatment was employed to prepare TiO2-based photocatalysts with distinct particle sizes and crystalline structures. The as prepared metal oxides were evaluated as photocatalysts for gaseous HCHO degradation, methanol, and dye oxidation reactions. Additionally, metallic platinum was deposited on the TiO2 surfaces and H2 evolution measurements were performed. The photocatalytic activities were rationalized in terms of morphologic parameters along with the electron/hole dynamics obtained from transient absorption spectroscopy (TAS). TiO2-2 exhibits smaller particle size, poorer crystallinity, and higher surface area than TiO2-1. Moreover the hydrothermal treatment leads to formation of the metastable brookite phase, while TiO2-1 exhibits only the anatase phase. TAS measurements show that the electron/hole recombination of TiO2-2 is faster than that of the latter. Despite that, TiO2-2 exhibits higher photonic efficiencies for photocatalytic oxidation reactions, which is attributed to its larger surface area that compensates for the decrease of the surface charge carrier concentration. For H2 evolution, it was found that the surface area has only a minor effect and the photocatalyst performance is controlled by the efficiency of the electron transfer to the platinum islands. This process is facilitated by the higher crystallinity of TiO2-1, which exhibits higher photonic efficiency for H2 evolution than that observed for TiO2-2. The results found here provide new insights into the correlations between thermal treatment conditions and photocatalytic activity and will be useful for the design of high performance photocatalysts. eng
dc.description.sponsorship Fundac˜ao de Amparo `a Pesquisa do Estado de Minas Gerais
dc.description.sponsorship Conselho Nacional de Desenvolvimento Cientif´ıco e Tecnolog´ıco
dc.description.sponsorship Coordenac˜ao de Aperfeiçoamento de Pessoal de N´ıvel Superior
dc.description.sponsorship DFG/BA 1137/8-2
dc.language.iso eng eng
dc.publisher Cambridge : Royal Society of Chemistry
dc.relation.ispartofseries RSC Advances 5 (2015), Nr. 86
dc.rights Es gilt deutsches Urheberrecht. Das Dokument darf zum eigenen Gebrauch kostenfrei genutzt, aber nicht im Internet bereitgestellt oder an Außenstehende weitergegeben werden. Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
dc.subject transient absorption-spectroscopy eng
dc.subject titanium-dioxide nanoparticles eng
dc.subject light-active tio2 eng
dc.subject hydrogen-production eng
dc.subject heterogeneous photocatalysis eng
dc.subject particle-size eng
dc.subject semiconductor photocatalysis eng
dc.subject tio2-based photocatalysts eng
dc.subject anatase nanoparticles eng
dc.subject aqueous-solution eng
dc.subject.ddc 540 | Chemie ger
dc.title Charge carrier dynamics and photocatalytic behavior of TiO2 nanopowders submitted to hydrothermal or conventional heat treatment eng
dc.type article
dc.type Text
dc.relation.issn 2046-2069
dc.bibliographicCitation.issue 86
dc.bibliographicCitation.volume 5
dc.bibliographicCitation.firstPage 70536
dc.bibliographicCitation.lastPage 70545
dc.description.version publishedVersion
tib.accessRights frei zug�nglich

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