Urea-glass preparation of titanium niobium nitrides and subsequent oxidation to photoactive titanium niobium oxynitrides.

Title Urea-glass preparation of titanium niobium nitrides and subsequent oxidation to photoactive titanium niobium oxynitrides.
Authors J.J. Brancho; A.D. Proctor; S. Panuganti; B.M. Bartlett
Journal Dalton Trans
DOI 10.1039/c7dt03077k
Abstract

Titanium niobium oxynitrides (TiNbON) are an attractive category of potential photocatalysts, but strategies for preparing them remain limited. We adapt the wet chemical "urea glass" method for pure transition metal nitrides to single-phase mixed-metal titanium niobium nitrides for a range of niobium mole fractions. We then oxidize the nitrides by heating in air to prepare titanium niobium oxynitride that absorbs visible light of ? ? 550 nm. The materials are characterized by powder X-ray diffraction, scanning electron microscopy, and diffuse reflectance UV-vis spectroscopy. Their photochemical activity as a function of Nb fraction is benchmarked with methylene blue photomineralization promoted by full-spectrum AM 1.5G solar irradiation with and without a ? ? 400 nm cut-on filter. First-order Langmuir-Hinshelwood rate constants for photomineralization reveal a composition with ?8% Nb to have superior reactivity. Full compositional analysis by Kjeldahl chemical nitrogen determination and energy-dispersive X-ray spectroscopy yields a chemical formula of Ti0.92Nb0.08O1.97N0.03. Finally, electron paramagnetic resonance spectroscopy correlates a localized Nb(4+) defect with increased photochemical reaction rate.

Citation J.J. Brancho; A.D. Proctor; S. Panuganti; B.M. Bartlett.Urea-glass preparation of titanium niobium nitrides and subsequent oxidation to photoactive titanium niobium oxynitrides.. Dalton Trans. 2017. doi:10.1039/c7dt03077k

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See more Niobium products. Niobium (atomic symbol: Nb, atomic number: 41) is a Block D, Group 5, Period 5 element with an atomic weight of 92.90638. Niobium Bohr ModelThe number of electrons in each of niobium's shells is 2, 8, 18, 12, 1 and its electron configuration is [Kr] 4d4 5s1. The niobium atom has a radius of 146 pm and a Van der Waals radius of 207 pm. Niobium was discovered by Charles Hatchett in 1801 and first isolated by Christian Wilhelm Blomstrand in 1864. In its elemental form, niobium has a gray metallic appearance. Niobium has the largest magnetic penetration depth of any element and is one of three elemental type-II superconductors (Elemental Niobiumalong with vanadium and technetium). Niobium is found in the minerals pyrochlore, its main commercial source, and columbite. The word Niobium originates from Niobe, daughter of mythical Greek king Tantalus.

Titanium

See more Titanium products. Titanium (atomic symbol: Ti, atomic number: 22) is a Block D, Group 4, Period 4 element with an atomic weight of 47.867. The number of electrons in each of Titanium's shells is [2, 8, 10, 2] and its electron configuration is [Ar] 3d2 4s2. Titanium Bohr ModelThe titanium atom has a radius of 147 pm and a Van der Waals radius of 187 pm. Titanium was discovered by William Gregor in 1791 and first isolated by Jöns Jakob Berzelius in 1825. In its elemental form, titanium has a silvery grey-white metallic appearance. Titanium's properties are chemically and physically similar to zirconium, both of which have the same number of valence electrons and are in the same group in the periodic table. Elemental TitaniumTitanium has five naturally occurring isotopes: 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Titanium is found in igneous rocks and the sediments derived from them. It is named after the word Titanos, which is Greek for Titans.

Nitrogen

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