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Materials (Basel)

Title:		"Hydrothermal Synthesis of Rare-Earth Modified Titania: Influence on Phase Composition, Optical Properties, and Photocatalytic Activity"
Author(s):		Rozman N; Tobaldi DM; Cvelbar U; Puliyalil H; Labrincha JA; Legat A; Sever Skapin A;
Address:		"Slovenian National Building and Civil Engineering Institute, Dimiceva 12, 1000 Ljubljana, Slovenia. nejc.rozman@zag.si. Department of Materials and Ceramic Engineering/CICECO-Aveiro Institute of Materials, Campus Universitario de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal. david.tobaldi@ua.pt. Department of Gaseous Electronics (F6), Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia. uros.cvelbar@guest.arnes.si. IMEC, Kapeldreef 75, 3001 Leuven, Belgium. hari.org88@gmail.com. Department of Materials and Ceramic Engineering/CICECO-Aveiro Institute of Materials, Campus Universitario de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal. jal@ua.pt. Slovenian National Building and Civil Engineering Institute, Dimiceva 12, 1000 Ljubljana, Slovenia. andraz.legat@zag.si. Slovenian National Building and Civil Engineering Institute, Dimiceva 12, 1000 Ljubljana, Slovenia. andrijana.skapin@zag.si"
Journal Title:		Materials (Basel)
Year:		2019
Volume:		20190228
Issue:		5
Page Number:		-
DOI:		10.3390/ma12050713
ISSN/ISBN:		1996-1944 (Print) 1996-1944 (Electronic) 1996-1944 (Linking)
Abstract:		"In order to expand the use of titania indoor as well as to increase its overall performance, narrowing the band gap is one of the possibilities to achieve this. Modifying with rare earths (REs) has been relatively unexplored, especially the modification of rutile with rare earth cations. The aim of this study was to find the influence of the modification of TiO(2) with rare earths on its structural, optical, morphological, and photocatalytic properties. Titania was synthesized using TiOSO(4) as the source of titanium via hydrothermal synthesis procedure at low temperature (200 degrees C) and modified with selected rare earth elements, namely, Ce, La, and Gd. Structural properties of samples were determined by X-ray powder diffraction (XRD), and the phase ratio was calculated using the Rietveld method. Optical properties were analyzed by ultraviolet and visible light (UV-Vis) spectroscopy. Field emission scanning electron microscope (FE-SEM) was used to determine the morphological properties of samples and to estimate the size of primary crystals. X-ray photoelectron spectroscopy (XPS) was used to determine the chemical bonding properties of samples. Photocatalytic activity of the prepared photocatalysts as well as the titania available on the market (P25) was measured in three different setups, assessing volatile organic compound (VOC) degradation, NO(x) abatement, and water purification. It was found out that modification with rare earth elements slows down the transformation of anatase and brookite to rutile. Whereas the unmodified sample was composed of only rutile, La- and Gd-modified samples contained anatase and rutile, and Ce-modified samples consisted of anatase, brookite, and rutile. Modification with rare earth metals has turned out to be detrimental to photocatalytic activity. In all cases, pure TiO(2) outperformed the modified samples. Cerium-modified TiO(2) was the least active sample, despite having a light absorption tail up to 585 nm wavelength. La- and Gd-modified samples did not show a significant shift in light absorption when compared to the pure TiO(2) sample. The reason for the lower activity of modified samples was attributed to a greater Ti(3+)/Ti(4+) ratio and a large amount of hydroxyl oxygen found in pure TiO(2). All the modified samples had a smaller Ti(3+)/Ti(4+) ratio and less hydroxyl oxygen"
Keywords:		TiO2 modification photocatalytic activity rare earths visible light activity;
Notes:		"PubMed-not-MEDLINERozman, Nejc Tobaldi, David M Cvelbar, Uros Puliyalil, Harinarayanan Labrincha, Joao A Legat, Andraz Sever Skapin, Andrijana eng PT2020 Partnership Agreement/FCT/MEC ; FEDER/ NC-0002 and No. P2-0273 and L2-7667/Slovenian Research A, Slovenian Ministry of Education, Science and Sportgency/ Promotion of the employment of young PhDs' program/Slovenian Ministry of Education, Science and Sportgency/ Switzerland 2019/03/03 Materials (Basel). 2019 Feb 28; 12(5):713. doi: 10.3390/ma12050713"