02510nas a2200193 4500008004100000022001400041245010000055210006900155260011000224300001600334490000700350520170600357100002502063700001802088700002302106700002802129700003002157856012902187 2014 eng d a1463-907600aElectronic structure-sunlight driven water splitting activity correlation of (Zn1-yGay)(O1-zNz)0 aElectronic structuresunlight driven water splitting activity cor aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a23654-236620 v163 a

(Zn1-yGay)(O1-zNz) (y <= 0.10; z <= 0.15) solid solutions have been investigated for their electronic structure and visible light photocatalytic activity, and a correlation was found between them. (Zn1-yGay)(O1-zNz) with ZnO as the major component have been synthesized by a solution combustion method in 10 minutes using simple raw materials. The local structures of Zn K edge and Ga K edge, and changes in the chemical environment with the incorporation of Ga and N in ZnO were determined by EXAFS study. EXAFS and XRD results suggested the dissolution of GaN in the ZnO lattice. The homogeneity of the solid solution was demonstrated from HRTEM studies. Photoluminescence studies revealed the creation of a new band at the top of the ZnO valence band (VB), and thus the broadening of the VB of (Zn1-yGay)(O1-zNz) or a decrease in the band gap was attributed to the origin of visible light absorption. UV-Vis spectral studies showed light absorption up to 550 nm, which directly supports the VB broadening. Predominant oxygen vacancies and high photocorrosion observed for ZnO were fully suppressed for (Zn1-yGay)(O1-zNz) , indicating the minimization of defects, and thus more sustainability under irradiation conditions. The bare solid solution exhibited reasonable and promising activity for solar hydrogen evolution and photoelectrochemical current generation at 0 V. The present work explained factors such as the preparation method, single phase structure with the stabilization of integral parts, homogeneity in the structure, compensation of oxygen vacancies, and suppression of the density of recombination centres that play a pivotal role in realizing solar energy harvesting.

1 aRajaambal, Sivaraman1 aYadav, A., K.1 aJha, Shambhu, Nath1 aBhattacharyya, Dibyendu1 aGopinath, Chinnakonda, S. uhttp://library.ncl.res.in/content/electronic-structure-sunlight-driven-water-splitting-activity-correlation-zn1-ygayo1-znz-001757nas a2200229 4500008004100000022001400041245011200055210006900167260011000236300001400346490000700360520082900367100002901196700002401225700003201249700002801281700002301309700002101332700002601353700001801379856013001397 2014 eng d a1477-922600aInvestigations into variations in local cationic environment in layered oxide series InGaO3(ZnO)(m) (m=1-4)0 aInvestigations into variations in local cationic environment in  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcNOV a2120-21260 v433 a

Layered oxides of the series InGaO3(ZnO)(m) (m = 1-4) are interesting due to their structural anisotropy. Here, we report a comprehensive study of their structural details, focusing on the local cationic environment in bulk powder samples by MASNMR and EXAFS, which is hitherto not attempted. It is found that the Ga geometry varies gradually from pure pentacoordinated to a mixture of penta and tetracoordinated with increasing amounts of tetracoordination as we move across the series, contrary to previous reports suggesting exclusively trigonal bipyramidal coordination in all the compounds. A similar observation is also made in the case of Zn and structural evolution involving the dissolution of Ga in a ZnO4 tetrahedral network in a sandwich layer can be discerned, as the insulating ZnO layer size increases.

1 aNarendranath, Soumya, B.1 aYadav, Ashok, Kumar1 aAjithkumar, Thalasseril, G.1 aBhattacharyya, Dibyendu1 aJha, Shambhu, Nath1 aDey, Krishna, K.1 aRaja, Thirumalaiswamy1 aDevi, Nandini uhttp://library.ncl.res.in/content/investigations-variations-local-cationic-environment-layered-oxide-series-ingao3znom-m1-4-002086nas a2200253 4500008004100000022001400041245013300055210006900188260007100257300001600328490000600344520111500350653002601465653001801491653001901509653001801528653003501546100002901581700002401610700002801634700002301662700001801685856012901703 2014 eng d a1944-824400aPhotocatalytic H-2 evolution from water-methanol system by anisotropic InFeO3(ZnO)(m) oxides without cocatalyst in visible light0 aPhotocatalytic H2 evolution from watermethanol system by anisotr a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a12321-123270 v63 a

InFeO3(ZnO)(m), series of oxides are found to give unprecedented H-2 evolution from water-methanol mixtures without using any cocatalysts. This family of compounds has an anisotropically layered structure in which Zn/FeOn polyhedra are sandwiched between InO6 octahedral layers. Local structure characterization by X-ray absorption spectroscopy reveals that Zn coordination changes from pentacoordinated to tetrahedral geometry across the series, whereas Fe geometry remains trigonal bipyramidal in all the compounds. This peculiar structure is conducive for a spatial separation of photogenerated charges reducing recombination losses. Band gap energies calculated from absorption spectra indicate potential visible light activity, and this may be due to the orbital mixing of Fe 3d and O 2p as revealed by pre-edge features of X-ray absorption spectra. Band positions are also advantageously placed for a visible light H-2 generation and is indeed found to be the case in methanol-assisted water splitting with standardized hydrogen evolution of similar to 19.5 mmol g(-1) h(-1) for all the catalysts.

10aanisotropic structure10aH-2 evolution10aInFeO3(ZnO)(m)10alayered oxide10aphotocatalytic water splitting1 aNarendranath, Soumya, B.1 aYadav, Ashok, Kumar1 aBhattacharyya, Dibyendu1 aJha, Shambhu, Nath1 aDevi, Nandini uhttp://library.ncl.res.in/content/photocatalytic-h-2-evolution-water-methanol-system-anisotropic-infeo3znom-oxides-without-000801nas a2200217 4500008004100000245010800041210006900149260000800218300001800226490000600244100002400250700002400274700002800298700002100326700002800347700002300375700001700398700002800415700001800443856012200461 2016 eng d00aNitrogen doping in oxygen-deficient Ca2Fe2O5: a strategy for efficient oxygen reduction oxide catalysts0 aNitrogen doping in oxygendeficient Ca2Fe2O5 a strategy for effic cNOV a34387–343950 v81 aJijil, Chamundi, P.1 aLokanathan, Moorthi1 aChithiravel, Sundaresan1 aNayak, Chandrani1 aBhattacharyya, Dibyendu1 aJha, Shambhu, Nath1 aBabu, P., D.1 aKakade, Bhalchandra, A.1 aDevi, Nandini uhttp://library.ncl.res.in/content/nitrogen-doping-oxygen-deficient-ca2fe2o5-strategy-efficient-oxygen-reduction-oxide