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N-Doped titanium dioxide nanosheets: Preparation, characterization and UV/visible-light activity
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SYSNO ASEP 0490488 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title N-Doped titanium dioxide nanosheets: Preparation, characterization and UV/visible-light activity Author(s) Barbieriková, Z. (SK)
Pližingrová, Eva (UACH-T) SAI, ORCID
Motlochová, Monika (UACH-T) SAI, RID, ORCID
Bezdička, Petr (UACH-T) SAI, RID, ORCID
Boháček, Jaroslav (UACH-T) SAI
Dvoranová, D. (SK)
Mazúr, M. (SK)
Kupčík, Jaroslav (UACH-T) SAI, RID, ORCID
Jirkovský, Jaromír (UFCH-W) RID
Šubrt, Jan (UACH-T) SAI, RID
Krýsa, J. (CZ)
Brezová, V. (SK)Number of authors 12 Source Title Applied Catalysis B - Environmental. - : Elsevier - ISSN 0926-3373
Roč. 232, SEP (2018), s. 397-408Number of pages 12 s. Language eng - English Country NL - Netherlands Keywords N-Doped titanium dioxide ; Photocatalysis ; EPR spectroscopy ; Lyophilization ; Spin trapping Subject RIV CA - Inorganic Chemistry OECD category Inorganic and nuclear chemistry Subject RIV - cooperation J. Heyrovsky Institute of Physical Chemistry - Physical ; Theoretical Chemistry R&D Projects LM2015073 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) 8X17016 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UACH-T - RVO:61388980 ; UFCH-W - RVO:61388955 UT WOS 000434004300044 EID SCOPUS 85044611201 DOI 10.1016/j.apcatb.2018.03.053 Annotation A series of nitrogen-doped 2D-titanium dioxide nanosheets was synthesized via green and facile procedure from the lyophilized aqueous colloids of peroxo titanic acid by urea addition and annealing in the temperature range of 350-500 degrees C. Detailed structural characterization (SEM, TEM with EDX, XRD) of N-doped TiO2 confirmed their 2D-foil morphology composed of packed anatase nanocrystals. CHNS analysis showed that the total nitrogen content in the N-doped TiO2 nanosheets is comparable (0.3 wt. %), and as shown in the EPR measurements in solid state, the annealing temperature determines the character of the nitrogen species incorporated in the anatase lattice. Paramagnetic nitrogen bulk centers (N-b(.)) dominate the X- and Q-band EPR spectra of the synthesized N-doped TiO2 annealed up to 400 degrees C, while NO species were detected in samples annealed at higher temperatures. The photoexcitation of the N-doped anatase nanosheets resulted in an intense increase of the N-b(.) signal intensity, especially upon VIS-light exposure, reflecting the selective photoexcitation of the material via diamagnetic N-b(-), centers. Nevertheless, the situation upon irradiation of dispersed systems is rather different and to link the information on the structure of the nanosheets with their photoinduced performance in suspensions, the indirect techniques of EPR spectroscopy were applied. Effective generation of paramagnetic reactive oxygen species (ROS) upon UV photoexcitation of the N-doped TiO2 nanopowders dispersed in water or dimethylsulfoxide was confirmed by EPR spin trapping technique. The VIS-light-induced ROS formation was significantly lower and correlates well with the results obtained by the photocatalytic decomposition of 4-chlorophenol upon VIS light. Even though the center dot OH-induced capacity of N-doped TiO2 prevails upon UV exposure, the VIS irradiation evokes the formation of photoelectrons capable of the selective reduction processes as demonstrated by the one-electron reduction of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation, where the form of nitrogen dopant (e. g. the presence of N-b(-)/N-b(.)) in the anatase structure showed a clear effect on the reaction rate. The prepared visible-light active N-doped TiO2 nanosheets exhibiting also adequate UV photoactivity represent promising materials for further development of solar-light active photocatalysts. Workplace Institute of Inorganic Chemistry Contact Jana Kroneislová, krone@iic.cas.cz, Tel.: 311 236 931 Year of Publishing 2019
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