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Istituto di ricerche sulla combustione
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Tipo: Articolo in rivista

Titolo: Simple Ethanol Refluxing Method for Production of Blue-Colored Titanium Dioxide with Oxygen Vacancies and Visible Light-Driven Photocatalytic Properties

Anno di pubblicazione: 2020

Formato: Elettronico

Autori: Stefano Lettieri, Valentina Gargiulo, Michela Alfč, Matteo Amati, Patrick Zeller, Valentin-Adrian Maraloiu, Fabio Borbone, Michele Pavone, Ana B. Muņoz-García, Pasqualino Maddalena

Affiliazioni autori: Institute of Applied Sciences and Intelligent Systems, National Research Council (ISASI-CNR), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy. Institute for Research on Combustion, National Research Council (IRC-CNR), Piazzale V. Tecchio 80, 80125 Napoli, Italy. Elettra Sincrotrone Trieste SCpA di interesse nazionale, SS14 Km 163-5, I-34149 Trieste, Italy National Institute of Materials Physics, 405 Atomistilor Str, 077125 Magurele, Romania. Dipartimento di Scienze Chimiche, Universitā degli Studi di Napoli "Federico II", Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy Dipartimento di Fisica, Universitā degli Studi di Napoli "Federico II", Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Napoli, Italy

Autori CNR:

  • MICHELA ALFE'
  • VALENTINA GARGIULO
  • STEFANO LETTIERI

Lingua: inglese

Abstract: We show that a simple ethanol (EtOH) refluxing treatment at mild temperature (120 °C) allows producing blue-colored and reduced titanium dioxide (TiO2-x) exhibiting improved visible-light (VIS) photocatalytic properties. The treatment causes an increase in the density of Ti(III) species and the appearance of two optical absorption features: a broad absorption band--responsible for the blue coloration--extending from the green region (~2.3 eV) up to the near-infrared and a subgap absorption tail close to the band gap energy. The experimental results combined with a computation of the density of states via hybrid Hartree-Fock density functional support the hypothesis that the EtOH reflux treatment leads to formation of surface and subsurface oxygen (O) vacancies. We also show that the excitation-resolved photoluminescence technique allows a high-contrast detection of a subgap optical excitation band peaked at about 430 nm (~2.9 eV), associated with anatase photoluminescence, whose intensity increases after the EtOH reflux treatment. This result gives a very direct support to the debated hypothesis identifying O vacancy states as the energy levels involved in the radiative transition of anatase TiO2. Improved photocatalytic degradation by the processed TiO2 under VIS illumination is demonstrated, and the possible mechanism involved in the formation of surface O vacancies is discussed. The method outlines a very simple, low-cost, and fast procedure to target the formation of O vacancies in the TiO2 surface region.

Lingua abstract: inglese

Rivista:

Journal of physical chemistry. C. American Chemical Society,
Paese di pubblicazione: Stati Uniti d'America
Lingua: inglese
ISSN: 1932-7455

DOI: 10.1021/acs.jpcc.9b08993

Referee: Sė: Internazionale

Stato della pubblicazione: Published version

Parole chiave:

  • Nanoparticles
  • Photocatalysis
  • Granular materials
  • Oxides
  • Ethanol
  • Defects in Solids
  • Minerals

URL: https://pubs.acs.org/doi/10.1021/acs.jpcc.9b08993

Strutture CNR:

 
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