Unraveling the Cooperative Mechanism of Visible-Light Absorption in Bulk N,Nb Codoped TiO2 Powders of Nanomaterials (Articolo in rivista)

Type
Label
  • Unraveling the Cooperative Mechanism of Visible-Light Absorption in Bulk N,Nb Codoped TiO2 Powders of Nanomaterials (Articolo in rivista) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1021/jp507143z (literal)
Alternative label
  • Marchiori, Chiara; Di Liberto, Giovanni; Soliveri, Guido; Loconte, Laura; Lo Presti, Leonardo; Meroni, Daniela; Ceotto, Michele; Oliva, Cesare; Cappelli, Serena; Cappelletti, Giuseppe; Aieta, Chiara; Ardizzone, Silvia (2014)
    Unraveling the Cooperative Mechanism of Visible-Light Absorption in Bulk N,Nb Codoped TiO2 Powders of Nanomaterials
    in Journal of physical chemistry. C
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Marchiori, Chiara; Di Liberto, Giovanni; Soliveri, Guido; Loconte, Laura; Lo Presti, Leonardo; Meroni, Daniela; Ceotto, Michele; Oliva, Cesare; Cappelli, Serena; Cappelletti, Giuseppe; Aieta, Chiara; Ardizzone, Silvia (literal)
Pagina inizio
  • 24152 (literal)
Pagina fine
  • 24164 (literal)
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  • 118 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 13 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo
  • 41 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • University of Milan; Italian CNR; Aarhus University; Consorzio Interuniv Nazl Sci & Tecnol Mat INSTM (literal)
Titolo
  • Unraveling the Cooperative Mechanism of Visible-Light Absorption in Bulk N,Nb Codoped TiO2 Powders of Nanomaterials (literal)
Abstract
  • N,Nb-codoping has recently been proposed as a promising strategy to enhance the activity of nanostructured TiO2 under visible irradiation. Here, we suggest a possible electronic mechanism to account for the observed visible absorption improvement. The effects of N and Nb species on the electronic, crystallographic, and morphological properties of TiO2 were deeply investigated both experimentally (HR-XRPD, EXAFS, EDX, BET, SEM, EPR, and DRS) and theoretically (DFT). We found a significant synergism between N and Nb species, while EXAFS, HR-XRPD, and DFT simulations provided compelling evidence for the Nb substitutional position in anatase. At variance with interstitial, substitutional Nb can transfer an electron to low-energy valence states of the N codopant near the valence band. This intrinsic charge compensation mechanism is substantiated by EPR, which shows a reduction of the paramagnetic bulk N species signal in N,Nb-codoped samples. DRS analysis of N,Nb-codoped samples shows a slight reduction of the apparent band gap and a significantly increased visible-light absorbance. This effect is due to the shallow midgap states created by Nb (below conduction band) and N (above valence band). DFT results suggest that substitutional Nb ions transfer electrons to low-lying guest N states within the band gap, eventually enhancing the light absorption. (literal)
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