Abstract
TiOx (x<2) nanoparticles have been synthesized by solid state reaction between as-prepared TiO2 nanoparticles and NaAlH4, KBH4 as a reducing agents in argon atmosphere at two temperature 600 oC and 850 oC . the X-ray diffraction patterns of reduced TiO2 shows a peak shift and broadening which attributed to the lattice contraction after reduction treatment. AFM images confirm that the surface roughness of reduced TiO2 were larger than unmodified TiO2 nanoparticles due to the formation of oxygen vacancies. UV‐Vis spectroscopy measurements revealed that the reduced TiO2 nanoparticles have an absorption edge lies in the visible region from the electromagnetic radiations with lower band gap. EDS spectra indicate that the as-prepared and reduced TiO2 nanoparticles have a high degree of purity and the acquired results confirm formation nonstoichiometric (TiO2-x) with oxygen deficient.
Highlights
Titanium dioxide TiO2 has been studied intensively, this is because of its chemical and biological inertness, high photocatalytic efficiency, environmental tolerance, large stability, and low cost [1]
Pure TiO2 is not a good material for practical applications because of the wide band gap (3.2 eV for anatase phase, and 3.0 eV for rutile phase), this mean it can be activated only under the UV radiations which make about 5% from the total solar radiation [9].There are many treatments to improve the photocatalytictic activity of TiO2 in visible light range, this methods include doping titanium dioxide with metal ions such as (Cu, Fe, V), and nonmetals such (C,N), and with rare earth elements and introducing defects into its structure [10]
It was thought that the introduced localized oxygen vacancy states that have energies of 0.75 to 1.18 eV below the conduction band minimum of TiO2 nanoparticles are less than the redox potential for evolution of hydrogen, which, in combination with the little electron mobility in the bulk region related to this localization, makes the photocatalytic activity of the reduced TiO2 insignificant [12]
Summary
Titanium dioxide TiO2 has been studied intensively, this is because of its chemical and biological inertness, high photocatalytic efficiency, environmental tolerance, large stability, and low cost [1]. It was thought that the introduced localized oxygen vacancy states that have energies of 0.75 to 1.18 eV below the conduction band minimum of TiO2 nanoparticles are less than the redox potential for evolution of hydrogen, which, in combination with the little electron mobility in the bulk region related to this localization, makes the photocatalytic activity of the reduced TiO2 insignificant [12]. Theoretical calculations estimate that a vacancy band of electronic states induced by high vacancy concentration can be a just below the conduction band[13] These results show that it is possible to construct visible-light responsive TiO2 through introducing oxygen vacancy or Ti+3[14]. In this work , TiO2 nanoparticles was prepared using a well known sol-gel method, the band gap of as-prepared TiO2 nanoparticles were modified using solid state reaction method in inert atmosphere with new reductant materials. These modified TiO2 nanoparticles having lower band gap as compared with unmodified TiO2
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