Characterization of Mo Doped TiO2 and its Enhanced Photo Catalytic Activity Under Visible Light

Abstract

Transition metal doping into the TiO 2 lattice can expand the response of these metal oxide nano particles to the visible region. In view of this, Mo 6+ ion is doped into the TiO 2 lattice in order to understand the mechanism of its photo response. The prepared photocatalysts were characterized by X-ray diffraction, UV-Visible absorption spectroscopy, UV-Visible diffuse reflectance spectroscopy, SEM, EDX, FTIR and BET specific surface area techniques. The characterization results have confirmed the incorporation of metal ions into TiO 2 lattice. XRD analysis shows no change in crystal structure except a slight variation in crystallite size and elongation along the c-axis with increase in the concentration of the dopant. Diffuse reflectance measurements showed a shift in the band edge position to longer wavelengths and an extension of the absorption to the visible region. The photo degradation efficiencies of these catalysts were studied with Tebuconazole pesticide as model pollutant. Under UV light, undoped catalyst showed higher activity than doped catalyst. But in the case of visible light irradiation Mo doped TiO 2 with intermediate dopant concentration of 0.06 atom % had the highest photocatalytic reactivity. This may be due to the narrowing of band gap so that it could effectively absorb the light of longer wavelength. The degradation path way was followed by UV-Visible spectroscopy.

Fabrication of La2Ti2O7 Crystals Using an Alkali-Metal Molybdate Flux Growth Method and Their Nitridability To Form LaTiO2N Crystals under a High-Temperature NH3 Atmosphere

“…In addition, a decrease in the photocatalytic efficiency with an excess amount of molybdenum in the La 2 Ti 2 O 7 because of the created mid band gaps, which act as recombination centers, should also be taken into account. 43 A slight change in the tolerance factor and octahedral tilting by the introduction of unintentional dopants (sodium and molybdenum) in the La 2 Ti 2 O 7 cannot be completely ignored to interpret the contribution of unintentional impurities upon incompletion of the La 2 Ti 2 O 7 -to-LaTiO 2 N transformation under nitridation using NH 3 at 950°C for 15 h. However, further studies need to be performed to confirm this. Figure 8 shows the UV−vis diffuse-reflectance spectra of the La 2 Ti 2 O 7 crystals grown using the K 2 MoO 4 flux and the LaTiO 2 N crystals fabricated by nitridation of the La 2 Ti 2 O 7 crystals grown using the NaCl and K 2 MoO 4 fluxes.…”

The Influence of Defects on Mo‐Doped TiO2 by First‐Principles Studies

“…The imaginary part e 2 (w) is calculated directly from the full many-electron wave function, and the real part e 1 (w) is then determined via a Kramers-Kronig transform. [31][32][33][34][35][36][37][38][39] Moreover, oxygen defects decrease the intensity of the absorption coefficient of Mo-doped systems in the visible range, and such a problem could be overcome by thermal treatment in an oxygen environment. The optical properties are determined by the bandgap, and so underestimation by DFT will lead to significant errors.…”

“…[31][32][33][34][35][36][37][38][39] The ionic radius of Mo 4 + is similar to that of Ti 4 + , and the four ionization potentials of Mo and Ti are close to each other. It is well known that oxygen defects will lead to an unpaired electron in the primitive cell, and in the absence of additional defects will turn the material into a conductor.…”

Visible Light Photocatalytic Degradation of Azo Dye and a Real Textile Wastewater Using Mn, Mo, La/TiO2 /AC Nanocomposite

“…Fourier-transform infrared spectra (FTIR) of the samples were prepared (Bruker, Model: VERTEX70, Germany) between the frequency ranges of 400-4000 cm −1 with KBr as a diluent 10 . The diffuse reflectance spectra (DRS) were obtained using a UV-visible spectrophotometer (JASCO, V-670-Japan) 43 . The surface characteristics and morphological features of nanocomposite and also elemental composition were studied using a field emission scanning electron microscope (FE-SEM, TESCAN microscope equipped with energy dispersive X-ray (EDX) microanalysis, Mira3, Kohoutovice, Czech Republic) 44 .…”