02498nas a2200265   4500008004100000022001400041245016100055210006900216260006900285300001200354490000800366520146200374653003801836653003001874653001901904653002301923653003601946653002001982100001802002700002002020700002202040700002502062700002402087856012102111       2009                        eng d  a0254-058400aDoping-induced microstructural, textural and optical properties of In2Ti1-xVxO5+delta semiconductors and their role in the photocatalytic splitting of water0 aDopinginduced microstructural textural and optical properties of  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcOCT  a399-4070 v1173 a<p>The physicochemical properties of V-doped indium titanates (In2Ti1-xVxO5-delta, 0.0 &lt;= x &lt;= 0.2) were investigated by using XPS, powder XRD, UV-vis, SEM and luminescence spectroscopy techniques. The Rietveld refinement of XRD data revealed that even though the V-containing samples were isostructural with In2TiO5 (orthorhombic space group Pnma), a systematic x-dependent variation was noticeable in the Ti-O bond lengths in [TiO6] octahedral units, cell parameters and in the value of delta. XPS results confirmed the coexistence of V5+ and V4+ states, leading thereby to an enhancement in oxygen non-stoichiometry in the doped samples. A loading-dependent progressive shift from 400 to 750 nm was also observed in the onset of the absorption edge, indicating a significant narrowing of the band gap. Furthermore, the samples with higher V-content were comprised of the grain clusters having larger size and an irregular shape. The UV-vis. photoluminescence and thermoluminescence studies indicate that the doping-induced lattice defects may give rise to certain closely spaced acceptor/donor energy levels in between the band gap of host matrix. The indium titanates are found to serve as stable photocatalysts for water splitting under visible light, where oxygen was the major reaction product. The role of microstructural and morphological properties in the photocatalytic activity is discussed. (C) 2009 Elsevier B.V. All rights reserved.</p>10aIn2Ti1-xVxO5+delta photocatalysts10aLuminescence spectroscopy10aMicrostructure10aOptical properties10aStructure-activity relationship10awater splitting1 aShah, Pallavi1 aBhange, Deu, S.1 aDeshpande, Aparna1 aKulkarni, Mukund, S.1 aGupta, Narendra, M.  uhttp://library.ncl.res.in/content/doping-induced-microstructural-textural-and-optical-properties-in2ti1-xvxo5delta-002852nas a2200229   4500008004100000022001400041245014600055210006900201260006900270300001200339490000800351520198800359653001902347653001502366653001902381653001902400653001902419100002202438700002102460700001802481856012302499       2011                        eng d  a0254-058400aRole of lattice defects and crystallite morphology in the UV and visible-light-induced photo-catalytic properties of combustion-prepared TiO20 aRole of lattice defects and crystallite morphology in the UV and  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR  a546-5540 v1263 a<p>The physico-chemical, photo-physical and micro-structural properties responsible for the strikingly different photocatalytic behavior of combustion-prepared TiO2 (c.TiO2) and Degussa P25 (d.TiO2) samples are elucidated in this study. Electron microscopy and selected area electron diffraction micrographs revealed that the two samples exhibited different morphologies. The grains of c.TiO2 were spherical and comprised of 5-6 nm size primary particle. On the other hand, d.TiO2 consisted of large (0.5-3.0 mu m) size and irregular shape aggregates having primary particles of 15-40 nm cross-sectional diameter. The ESR study revealed that the presence of certain defect states in c.TiO2 helped in stabilization of O-. and Ti3+-OH type species during room-temperature UV-irradiation. No such paramagnetic species were however formed over d.TiO2 under similar conditions. C1s and Ti 2p XPS spectra provide evidence for the presence of some lattice vacancies in c.TiO2 and also for the bulk Ti4+ -&gt; Ti3+ conversion during its UV-irradiation. Compared to d.TiO2, c.TiO2 displayed considerably higher activity for discoloration of methyl orange but very poor activity for splitting of water, both under UV and visible light radiations. This is attributed to enhanced surface adsorption of dye molecules over c.TiO2, because of its textural features and also the presence of photo-active ion-radicals. On the other hand, the poor activity of c.TiO2 for water splitting is related to certain defect-induced inter-band charge trapping states in the close vicinity of valence and conduction bands of c.TiO2, as revealed by thermoluminescence spectroscopy. Further, the dispersion of nanosize gold particles gave rise to augmented activity of both the catalysts, particularly for water splitting. This is explained by the promotional role of Au-0 or Au-0/TiO2 interfacial sites in the adsorption and charge-adsorbate interaction processes. (C) 2011 Elsevier B.V. All rights reserved.</p>10aBand-structure10aInterfaces10aMicrostructure10aNanostructures10aSemiconductors1 aDeshpande, Aparna1 aMadras, Giridhar1 aGupta, N., M.  uhttp://library.ncl.res.in/content/role-lattice-defects-and-crystallite-morphology-uv-and-visible-light-induced-photo-0