Magnéli phases Ti{sub 4}O{sub 7} and Ti{sub 8}O{sub 15} and their carbon nanocomposites via the thermal decomposition-precursor route

Journal Article · Tue Sep 15 00:00:00 EDT 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2015.04.037· OSTI ID:22486770

Veremchuk, I. ^[1]; Reibold, M. ^[2]; Matthey, B.; Michaelis, A. ^[3]; Grin, Yu. ^[1]; Kinski, I. ^[3]

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1. Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany)
2. Technical University of Dresden, Zum Triebenberg 50, 01328 Dresden (Zaschendorf) (Germany)
3. Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany)

A new synthetic approach for producing nano-powders of the Magnéli phases Ti{sub 4}O{sub 7}, Ti{sub 8}O{sub 15} and their carbon nanocomposites by thermal decomposition-precursor route is proposed. The formation mechanism of the single-phase carbon nanocomposites (Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C) from metal–organic precursors is studied using FT-IR, elemental analysis, TG, STA-MS and others. The synthesis parameters and conditions were optimized to prepare the target oxides with the desired microstructure and physical properties. The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. These nano-materials are n-type semiconductors with relatively low thermal conductivity in contrast to the bulk species. The nanostructured carbon nanocomposites of Magnéli phases achieve a low thermal conductivity close to 1 W/m K at RT. The maximum ZT{sub 570} {sub °C} values are 0.04 for Ti{sub 4}O{sub 7}/C powder nanocomposite and 0.01 for Ti{sub 8}O{sub 15}/C bulk nanocomposite. - Graphical abstract: From the precursor to the produced titanium oxide pellet and its microstructure (SEM, TEM micrographs) as well as results of phase and thermoelectric analyses. - Highlights: • Magnéli phases Ti{sub 4}O{sub 7}/Ti{sub 8}O{sub 15} via thermal decomposition-precursor route is proposed. • The formation mechanism of the nanocomposites Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • Microstructure of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are examined. • The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • The maximum figure of mertit ZT{sub 570} {sub °C} of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are 0.01 and 0.04.

• OSTI ID: 22486770
• Journal Information: Journal of Solid State Chemistry, Vol. 229; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
FOURIER TRANSFORMATION
INFRARED SPECTRA
MICROSTRUCTURE
NANOCOMPOSITES
NANOSTRUCTURES
POWDERS
PYROLYSIS
SCANNING ELECTRON MICROSCOPY
SEMICONDUCTOR MATERIALS
SYNTHESIS
THERMAL CONDUCTIVITY
THERMOELECTRIC MATERIALS
THERMOELECTRIC PROPERTIES
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY