Consequences of Nitrogen Doping and Oxygen Enrichment on Titanium Local Order and Photocatalytic Performance of TiO2 Anatase Articles uri icon

authors

  • Krivtsov, Igor
  • Ilkaeva, Marina
  • SALAS COLERA, EDUARDO
  • Amghouz, Zakariae
  • Garcia, Jose R.
  • Diaz, Eva
  • Ordo¿z, Salvador
  • Villar Rodil, Silvia

publication date

  • March 2017

start page

  • 6770

end page

  • 6780

issue

  • 12

volume

  • 121

International Standard Serial Number (ISSN)

  • 1932-7447

Electronic International Standard Serial Number (EISSN)

  • 1932-7455

abstract

  • Extended X-ray absorption fine structure (EXAFS) investigation of the oxygen-rich titania formed via the thermal treatment of N-doped TiO2 has revealed that the removal of N-dopants is responsible for the creation of defect sites in the titanium environment, thus triggering at high temperatures (500&-800 °C) the capture of atmospheric oxygen followed by its diffusion toward the vacant sites and formation of interstitial oxygen species. The effect of the dopants on Ti coordination number and Ti&-Oint and Ti&-Nint bond distances has been estimated. The photocatalytic p-cresol degradation tests have demonstrated that the interband states formed by the N-dopants contribute to a greater extent to the visible-light activity than the oxygen interstitials do. However, under the UV irradiation the oxygen-rich titania shows higher efficiency in the pollutant degradation, while the N-dopants in N&-TiO2 play the role of recombination sites. The presence of the surface nitrogen species in TiO2 is highly beneficial for the application in partial photooxidation reactions, where N&-TiO2 demonstrates a superior selectivity of 5-hydroxymethyl furfural (HMF) oxidation to 2,5-furandicarboxaldehyde (FDC). Thus, this work underlines the importance of a rational design of nonmetal doped titania for photocatalytic degradation and partial oxidation applications, and it establishes the role of bulk defects and surface dopants on the TiO2 photooxidation performance.