Solid-Gas Phase Photo-Catalytic Behaviour of Rutile and TiO n (1 < n < 2) Sub-Oxide Phases for Self-Cleaning Applications.

Autor: Nuño M; BRE Centre for Innovative Construction Materials (CICM), Department of Architecture and Civil Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK. manuelnunotutor@hotmail.com., Adamaki V; Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK. V.Adamaki@bath.ac.uk., Tobaldi DM; Department of Materials and Ceramic Engineering/CICECO-Aveiro Institute of Materials, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal. david.tobaldi@ua.pt., Hortigüela Gallo MJ; Center for Mechanical Technology and Automation-TEMA, Department of Mechanical Engineering, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal. mhortiguela@ua.pt., Otero-Irurueta G; Center for Mechanical Technology and Automation-TEMA, Department of Mechanical Engineering, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal. otero.gonzalo@ua.pt., Bowen CR; Department of Mechanical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK. c.r.bowen@bath.ac.uk., Ball RJ; BRE Centre for Innovative Construction Materials (CICM), Department of Architecture and Civil Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK. r.j.ball@bath.ac.uk.
Jazyk: angličtina
Zdroj: Materials (Basel, Switzerland) [Materials (Basel)] 2019 Jan 07; Vol. 12 (1). Date of Electronic Publication: 2019 Jan 07.
DOI: 10.3390/ma12010170
Abstrakt: The solid-gas phase photo-catalytic activities of rutile TiO₂ and TiO n (1 < n < 2) sub-oxide phases have been evaluated. Varying concentrations of Ti 3+ defects were introduced into the rutile polymorph of titanium dioxide through carbo-thermal reduction at temperatures ranging from 350 °C to 1300 °C. The resulting sub-oxides formed were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, impedance spectroscopy and UV-visible diffuse reflectance spectroscopy. The presence of Ti 3+ in rutile exposed to high reduction temperatures was confirmed by X-ray diffraction. In addition, a Ti 3+ -Ti 4+ system was demonstrated to enhance the photo-catalytic properties of rutile for the degradation of the air pollutants NO₂ and CO₂ under UV irradiation of wavelengths (λ) 376⁻387 nm and 381⁻392 nm. The optimum reduction temperature for photo-catalytic activity was within the range 350⁻400 °C and attributed to improved charge-separation. The materials that were subject to carbo-thermal reduction at temperatures of 350 °C and 400 °C exhibited electrical conductivities over one hundred times higher compared to the non-reduced rutile. The results highlight that sub-oxide phases form an important alternative approach to doping with other elements to improve the photo-catalytic performance of TiO₂. Such materials are important for applications such as self-cleaning where particles can be incorporated into surface coatings.
Databáze: MEDLINE
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