In-situ co-doping of sputter-deposited TiO₂:WN films for the development of photoanodes intended for visible-light electro-photocatalytic degradation of emerging pollutants.

Delegan, Nazar; Pandiyan, Rajesh; Komtchou, Simon; Dirany, Ahmad; Drogui, Patrick ORCID: https://orcid.org/0000-0002-3802-2729 et El Khakani, My Ali (2018). In-situ co-doping of sputter-deposited TiO₂:WN films for the development of photoanodes intended for visible-light electro-photocatalytic degradation of emerging pollutants. Journal of Applied Physics , vol. 123 , nº 20. p. 205101. DOI: 10.1063/1.5025830.

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Résumé

We report on the magnetron sputtering deposition of in-situ codoped TiO₂:WN films intended for electro-photocatalytic (EPC) applications under solar irradiation. By varying the RF-magnetron sputtering deposition parameters, we were able to tune the in-situ incorporation of both N and W dopants in the TiO₂ films over a wide concentration range (i.e., 0–9 at. % for N and 0–3 at. % for W). X-ray photoelectron spectroscopy analysis revealed that both dopants are mostly of a substitutional nature. The analysis of the UV-Vis transmission spectra of the films confirmed that the optical bandgap of both TiO₂:N and TiO₂:WN films can be significantly narrowed (from 3.2 eV for undoped-TiO₂ down to ∼2.3 eV for the doped ones) by tuning their dopant concentrations. We were thus able to pinpoint an optimal window for both dopants (N and W) where the TiO₂:WN films exhibit the narrowest bandgap. Moreover, the optimal codoping conditions greatly reduce the recombination defect state density compared to the monodoped TiO₂:N films. These electronically passivated TiO₂:WN films are shown to be highly effective for the EPC degradation of atrazine (pesticide pollutant) under sunlight irradiation (93% atrazine degraded after only 30 min of EPC treatment). Indeed, the optimally codoped TiO₂:WN photoanodes were found to be more efficient than both the undoped-TiO₂ and equally photosensitized TiO₂:N photoanodes (by ∼70% and ∼25%, respectively) under AM1.5 irradiation.

Type de document:	Article
Mots-clés libres:	energy gap; herbicides; irradiation; magnetron sputtering; pollution; semiconductor doping; X ray photoelectron spectroscopy
Centre:	Centre Eau Terre Environnement
Date de dépôt:	08 juin 2018 19:54
Dernière modification:	15 févr. 2022 15:54
URI:	https://espace.inrs.ca/id/eprint/7276

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