02352nas a2200181   4500008004100000022001400041245012400055210006900179260010400248300002300352520157100375100001801946700002501964700002001989700001402009700001802023856012902041       2008                        eng d  a1110-662X00aEffect of gold dispersion on the photocatalytic activity of mesoporous titania for the vapor-phase oxidation of acetone0 aEffect of gold dispersion on the photocatalytic activity of meso  a410 PARK AVENUE, 15TH FLOOR, \#287 PMB, NEW YORK, NY 10022 USAbHINDAWI PUBLISHING CORPORATIONcJAN  aArticle No. 7891493 a<p>Mesostructured titanium dioxide photocatalyst, having uniform crystallite size (6-12 nm) and average pore diameter of similar to 4.2 nm, was synthesized by using a low-temperature nonsurfactant hydrothermal route, employing tartaric acid as a templating agent. Gold additions from 0.5 to 2wt% were incorporated, either during the hydrothermal process or by postsynthesis wet impregnation. Compared to the impregnation-prepared samples, the samples synthesized hydrothermally contained smaller-size (&lt;= 1 nm) gold clusters occluded in the pores of the host matrix. Whereas CO(2) and H(2)O were the main reaction products in UV-assisted vapor-phase oxidation of acetone using these catalysts, C(2)H(6) and HCO(2)CH(3) were also produced for higher acetone concentrations in air. The conversion of acetone was found to increase with decrease in the size of both TiO(2) and gold particles. In situ IR spectroscopy revealed that titania and gold particles serve as independent adsorption and reaction sites for acetone and oxygen molecules. Acetone molecules adsorb exclusively at TiO(2) surface, giving rise to a strongly adsorbed (condensed) state as well as to the formation of formate- and methyl formate- type surface species. Hydroxyl groups at titania surface participate directly in these adsorption steps. Nanosize gold particles, on the other hand, were primarily responsible for the adsorption and activation of oxygen molecules. Mechanistic aspects of the photochemical processes are discussed on the basis of these observations. Copyright (C) 2008.</p>1 aAwate, S., V.1 aBelhekar, Anagha, A.1 aBhagwat, S., V.1 aKumar, R.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/effect-gold-dispersion-photocatalytic-activity-mesoporous-titania-vapor-phase-oxidation-002373nas a2200265   4500008004100000022001400041245013900055210006900194260011700263300001200380490000800392520134900400653002401749653002001773653001801793653002701811653002101838653002201859100001801881700001701899700002701916700001401943700001801957856013201975       2009                        eng d  a0920-586100aPhotocatalytic mineralization of benzene over gold containing titania nanotubes: role of adsorbed water and nanosize gold crystallites0 aPhotocatalytic mineralization of benzene over gold containing ti  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbCatalysis Soc India; Petrotech Soc; Indo US Sci & Technol ForumcMAR  a144-1510 v1413 a<p>Well aligned titania nanotubes, with surface area of similar to 150 m(2) g(-1) and average pore diameter of similar to 5 nm, have been synthesized by subjecting a mesoporous TiO(2) sample to alkaline treatment followed by calcination at different temperatures. Composite catalysts with gold particles dispersed in these nanotubes were also synthesized and their structural, morphological, optical and photocatalytic properties were examined. The catalytic activity of TiO(2) for UV-mediated photo-oxidation of benzene was found to be affected by several factors, such as the sample texture. presence of adsorbed water and gold crystallites. The overall conversion of benzene to form CO(2) followed a trend: Au/nanotube &gt; TiO(2) nanotubes &gt; mesoporous TiO(2). In situ IR spectroscopy revealed that the adsorption and reaction of benzene molecules gave rise to formation of certain phenolic species over TiO(2), while the temperature-programmed desorption (TPD) study showed that the Au/TiO(2) interfaces serve as distinct sites for the adsorption and activation of oxygen molecules. It is suggested that certain hydroxyl and oxygen ion radicals produced under UV-irradiation may promote the deep oxidation of surface phenolic species and phenoxyl (ArO center dot) type transient radicals. (c) 2008 Elsevier B.V. All rights reserved.</p>10aBenzene degradation10aGold containing10aPhotocatalyst10aRole of adsorbed water10aTiO(2) nanotubes10aTransient species1 aAwate, S., V.1 aSahu, R., K.1 aKadgaonkar, Mahesh, D.1 aKumar, R.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/photocatalytic-mineralization-benzene-over-gold-containing-titania-nanotubes-role-adsorbed-002501nas a2200217   4500008004100000022001400041245013500055210006900190260005700259300001400316490000700330520168200337100001502019700001502034700002002049700002102069700002702090700001802117700001802135856013002153       2011                        eng d  a0022-246100aRole of doping-induced photochemical and microstructural properties in the photocatalytic activity of InVO4 for splitting of water0 aRole of dopinginduced photochemical and microstructural properti  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcAUG  a5466-54760 v463 a<p>We report in this paper on microstructural, optical and photocatalytic properties of single-phase indium orthovanadates, as a function of doping at lattice sites. The UV-visible spectra of these samples exhibited intense UV-region bands at 250 and 350 nm, besides broad absorption band in visible region (350-700 nm). The wavelength at absorption edge and the intensity of visible absorption showed considerable increase on doping of an impurity, particularly at V or O lattice sites. Also, the samples gave rise to blue-green photoluminescence emission, with overriding bands at ca. 420, 450, 460 and 485 nm, on excitation at 240-420 nm wavelengths. The intensity of these fluorescence bands varied with excitation wavelength and impurity content of a sample. In deviation with several earlier studies, only oxygen and no hydrogen were produced during photocatalytic splitting of water, in the experiments conducted under visible light (&gt; 395 nm) and at a pH of similar to 6.5. The O-2 yield depended on the dispersed metal co-catalyst, impurity content and the addition of methanol as sacrificial reagent. On the other hand, small quantities of hydrogen and no oxygen were evolved on UV-irradiation of pure water using metal/InVO4. These results are ascribed to flat band potentials and the doping-induced inter-band donor and acceptor charge trapping states of InVO4, the presence of which is revealed by XRD, luminescence and XPS studies. Our study also confirms that the onset of absorption edge may not necessarily correspond to band-to-band energy gap of a semiconducting material. This accounts for some anomalous band gap energies reported earlier for InVO4.</p>1 aRakesh, K.1 aKhaire, S.1 aBhange, Deu, S.1 aDhanasekaran, P.1 aDeshpande, Suvarna, S.1 aAwate, S., V.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/role-doping-induced-photochemical-and-microstructural-properties-photocatalytic-activity-002853nas a2200229   4500008004100000022001400041245014600055210006900201260006900270300001200339490000800351520198800359653001902347653001502366653001902381653001902400653001902419100002202438700002102460700001802481856012402499       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.  uhttps://library.ncl.res.in/content/role-lattice-defects-and-crystallite-morphology-uv-and-visible-light-induced-photo-002739nas a2200193   4500008004100000022001400041245018300055210006900238260011000307300001600417490000700433520188100440100001802321700002702339700001502366700002102381700001802402856012502420       2011                        eng d  a1463-907600aRole of micro-structure and interfacial properties in the higher photocatalytic activity of TiO2-supported nanogold for methanol-assisted visible-light-induced splitting of water0 aRole of microstructure and interfacial properties in the higher   aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY  a11329-113390 v133 a<p>This paper deals with the textural, microstructural and interfacial properties of Au/TiO2 nanocomposites, in relation to their photocatalytic activity for splitting of water. TiO2 samples of two different morphologies were employed for dispersing different cocatalysts, such as: Au, Pt, Ag or Cu, for the sake of comparison. The samples were characterized using powder XRD, XPS, UV-visible, thermoluminescence, SEM, HRTEM and SAED techniques. Compared to other metal/TiO2 photocatalysts, Au/TiO2 with an optimum gold loading of 1 wt% was found to exhibit considerably higher activity for visible light induced production of H-2 from splitting water in the presence of methanol. Further, the sol-gel prepared TiO2 (s.TiO2), having spherical grains of 10-15 nm size, displayed better photoactivity than a Degussa P25 catalyst. The electron microscopy investigations on s.TiO2 revealed significant heterogeneity in grain morphology of individual TiO2 particles, exposure of the lattice planes, metal dispersion, and the interfacial metal/TiO2 contacts. The gold particles were found to be in a better dispersed state. O-2 TPD experiments revealed that the gold nanoparticles and Au/TiO2 interfaces may serve as distinct binding sites for adsorbate molecules. At the same time, our thermoluminescence measurements provide an insight into Au-induced new defect states that may facilitate the semiconductor-to-metal charge transfer transition. In conclusion, the superior photocatalytic activity of Au/TiO2 may relate to the grain morphology of TiO2, dispersion of gold particles, and the peculiar architecture of metal/oxide heterojunctions; giving rise in turn to augmented adsorption of reactant molecules and their interaction with the photo-generated e(-)/h(+) pair. The role played by methanol as a sacrificial reagent in photocatalytic splitting of water is discussed.</p>1 aAwate, S., V.1 aDeshpande, Suvarna, S.1 aRakesh, K.1 aDhanasekaran, P.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/role-micro-structure-and-interfacial-properties-higher-photocatalytic-activity-tio2-002032nas a2200217   4500008004100000022001400041245013700055210006900192260010600261300001400367490000700381520115400388653002501542653002301567653002401590653001501614653001901629100002101648700001801669856012701687       2012                        eng d  a0025-540800aEffects of grain morphology, microstructure and dispersed metal cocatalyst on the photoreduction of water over impurity-doped LaInO30 aEffects of grain morphology microstructure and dispersed metal c  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY  a1217-12280 v473 a<p>The single phase lanthanum indates doped with Ga (for La) and N (for O), i.e. La1-xGaxInO3 (0 &lt;= x &lt;= 0.2) and LaInO1-yNy (y similar to 0.6), exhibit significant activity for photoreduction of water; the yield of H-2 produced depending on dopant, excitation source, and addition of a sacrificial reagent. The two-step H-2 evolution observed for this reaction corresponds with the two distinct absorbance regimes displayed by these materials, one in UV-region due to bandgap excitation and the other in visible region arising from the transitions involving sub-bandgap donor or acceptor energy states. The photocatalytic activity of these d(10) metal oxides increases on coating with a metal/metal oxide co-catalyst, gold exhibiting superior activity to Pt and NiO, irrespective of excitation source and sample composition. The preparation-controlled particle morphology, doping-induced lattice imperfections, and metal/semiconductor hetero-junctions are envisaged to play a key role in the absorption characteristics and photocatalytic water reduction activity of metal/LaInO3 nanocomposites. (C) 2012 Elsevier Ltd. All rights reserved.</p>10aCatalytic properties10aChemical synthesis10aElectron microscopy10aInterfaces10aSemiconductors1 aDhanasekaran, P.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/effects-grain-morphology-microstructure-and-dispersed-metal-cocatalyst-photoreduction-001906nas a2200217   4500008004100000022001400041245011800055210006900173260010600242300001400348490000700362520106600369653001101435653002401446653001901470653001801489653002001507100002101527700001801548856012201566       2012                        eng d  a0360-319900aFactors affecting the production of H-2 by water splitting over a novel visible-light-driven photocatalyst GaFeO30 aFactors affecting the production of H2 by water splitting over a  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR  a4897-49070 v373 a<p>A d(10) photocatalyst, GaFeO3 having a band gap of similar to 2.7 eV, exhibits significant activity for the overall splitting of water under visible light (&gt;395 nm) irradiation, in the absence of sacrificial reagent or a noble metal co-catalyst. The doping of an anion led to considerable enhancement in activity, the S-doped catalysts displaying better activity compared to the samples containing nitrogen. Even though the H-2/O-2 yields were affected by preparation-dependent grain morphology, no direct relationship was observed between the photoactivity of a sample and its specific surface area. The techniques of HRTEM, SEM, XPS, Laser Raman, UV-visible and photoluminescence spectroscopy have enabled to demonstrate that, besides the grain morphology, certain lattice imperfections and microstructure may also play a crucial role in water splitting activity of a photocatalyst. The factors responsible for catalyst deactivation are examined. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.</p>10aGaFeO310ahydrogen production10aMicrostructure10aPhotocatalyst10awater splitting1 aDhanasekaran, P.1 aGupta, N., M.  uhttps://library.ncl.res.in/content/factors-affecting-production-h-2-water-splitting-over-novel-visible-light-driven-0