Routes to visible light active C-doped TiO2 photocatalysts using carbon atoms from the Ti precursors

Abstract

Publication information Journal of Photochemistry and Photobiology A-Chemistry, 289 :Publisher Elsevier Item record/more information http://hdl.handle.net/10197/5640 Publisher's statementThis is the author's version of a work that was accepted for publication in Journal of Photochemistry and Photobiology A: Chemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Photochemistry and Photobilogy (VOL 289, ISSUE 2014, (2014 AbstractIn this work, different thermal treatments of titanium isopropoxide-derived photo-catalyst precursors, designed with the purpose of generating C-doped TiO 2 photo-catalysts using carbon atoms present in the TiOx gel precursors as dopants, are presented. Specifically, these look at varying the standard calcination techniques using heat treatments in He (rather than calcination in air) and lower temperature calcinations (200 °C rather than 500 °C). The formed materials are characterised using N 2 physisorption, XRD, UV Visible spectroscopy and XPS and their activities in promoting the oxidation of 4-chlorophenol under visible-light-only conditions were analysed. The nature of carbon remaining on the (or in the) material is discussed found to be both surface graphitic carbon and carbon present in anionic dopant positions. The different contributions of each type of carbon to the catalytic photo-activity under visible light are discussed.

Deposition of Visible Light-Active C-Doped Titania Films via Magnetron Sputtering Using CO2 as a Source of Carbon

“…Compared to N-doping, C-doping is a considerably less studied field, mainly due to fact that synthesis routes for C-doped TiO 2 photocatalysts often involve multiple stages and/or unstable and costly reagents [ 19 ]. Nevertheless, a number of studies that are available indicate that carbon doping is a promising method for the enhancement of titania photocatalytic activity [ 21 , 22 ] due to band gap narrowing and the extended lifetime of photogenerated electrons and holes. The well-known fact that carbon-doped titania photocatalysts can have very different characteristics, with carbon found in interstitial, as well as in substitutional positions in the titania lattice, depending on the synthesis route, means that the choice of production technique is of particular importance in this case.…”

Synthesis and Structure of Carbon‐doped TiO2 by Carbothermal Treatment

“…[12] Starting with titanium carbide, carbondoped TiO 2 (C-TiO 2 ) can be produced by controlled oxidation in air at temperatures in the range of 350-400 • C [13] or by a two-step process where the oxidation in air is followed by annealing in oxygen at 600 • C. [14] A low-temperature method for the transformation of TiC into carbon-doped TiO 2 was investigated by Gu et al who treated a mixture of TiC with ethanol and nitric acid at 60 • C and obtained C-TiO 2 after drying at 120 • C. [15] Sol-gel methods are widely investigated as the process is comparably simple and no extra carbon source is needed. Metal-organic compounds such as titanium isopropoxide, [16][17][18] or titanium butoxide [19] are used. A sol-gel process followed by a calcination step, typically in the temperature range between 400 • C and 800 • C, yields the carbon-doped titanium oxide powder.…”

Decolorization of Reactive Black 5 Using N-Doped TiO2

“…A wide band gap of TiO2 involves UV irradiation (λ< 400 nm) due to requirement of higher photon energy. In an attempt to utilize solar energy and to promote photocatalytic efficiency of TiO2, doping with non-metal elements such as nitrogen (N) [8][9][10][11], sulfur (S) [12,13] and carbon (C) [14,15] has been employed. Among these elements, doping TiO2 with nitrogen was accepted as the most effective as a visible photocatalyst [9,11].…”