Structures, preparation and applications of titanium suboxides

Abstract

The crystal structure, physical and chemical properties, preparation methods and applications of titanium suboxides (TinO2n−1, n = integer greater than one) have recently attracted tremendous attention.

Electrocatalysts for PEM Fuel Cells

“…[122] Among these distinct oxides, conductivity increases with decreasing n (Figure 12), and the most reduced member of this series, Ti 4 O 7 , shows conductivity comparable to that of graphite. [124] For example, Ti 4 O 7 was synthesized by thermal reduction of TiO 2 with H 2 , [125][126][127][128] carbothermal reduction of TiO 2 with carbon [129] /organic materials [130][131][132] /carbon in molten salt, [133] and chemical reduction of TiO 2 with titanium [107] / zirconium [134] /CaH 2 . [124] For example, Ti 4 O 7 was synthesized by thermal reduction of TiO 2 with H 2 , [125][126][127][128] carbothermal reduction of TiO 2 with carbon [129] /organic materials [130][131][132] /carbon in molten salt, [133] and chemical reduction of TiO 2 with titanium [107] / zirconium [134] /CaH 2 .…”

Hydrogenation of Pyridines Using a Nitrogen‐Modified Titania‐Supported Cobalt Catalyst

“…Furthermore,t oi nvestigate the chemoselectivity for this hydrogenation process,p yridines bearing phenyl, benzyl, amide or acid groups were tested. Here,3 -, and 4-phenylpyridine as well as 2-benzylpyridine were hydrogenated to the corresponding piperidines without hydrogenation of the phenyl ring ( Table 1, entries [14][15][16]. Additionally,i sonicotinamide and isonicotinic acid were successfully converted to piperidine-4-carboxamide (2m)and piperidine-4-carboxylic acid (2n)s imply using water as solvent (Table 1, entries 17,18).…”

“…If the temperature of the treatment procedure is increased to 800 8 8C, the relative intensity of the TiO 2 -phase reflection peaks decreases and broad reflection peaks appear, which can be interpreted as the formation of titania suboxides of the general formula Ti x O 2xÀ1 . [14] Anyway,t he diffraction data does not allow the…”

Formation mechanism of Ti4O7 phase prepared by carbothermal reduction reaction

“…This unique crystal structure endows Ti n O 2 n −1 with excellent electrical and chemical properties, including great visible light response due to the narrower bandgap compared with traditional TiO 2 , high electrical conductivity, and superior electrochemical stability . Among these compounds, Ti 4 O 7 attracts the most attention in the fields of lithium‐sulfur batteries, photocatalysis, electrocatalytic, and thermoelectric due to its extremely high electrical conductivity (~1995 S/cm) and excellent electrochemical properties …”

“…5,6 Among these compounds, Ti 4 O 7 attracts the most attention in the fields of lithium-sulfur batteries, 7,8 photocatalysis, 9 electrocatalytic, 10,11 and thermoelectric 12,13 due to its extremely high electrical conductivity (~1995 S/cm 14 ) and excellent electrochemical properties. [15][16][17] Various studies have been conducted to prepare Ti 4 O 7 with different microstructures, including spheroid, 18 nanowires, 19 and nanotubes, 20 etc Carbothermal reduction reaction (CRR) is widely used to synthesis Ti 4 O 7 by using TiO 2 and carbon as titanium source and reducing agent, respectively, because of their advantages of low cost, abundance, and environment-friendly. 21 However, the phase evolution and microstructures during the CRR preparation process lack deep investigation, and there are seldom publications focused on the reaction mechanism of the fabrication process.…”