02314nas a2200241   4500008004100000022001400041245011900055210006900174260008900243300001200332490000800344520137100352653002601723653002801749653001901777653001401796653001201810653002501822100003201847700003201879700003001911856013101941       2009                        eng d  a0169-433200aElectronic decoupling of surface layers from bulk and its influence in oxidation catalysis: a molecular beam study0 aElectronic decoupling of surface layers from bulk and its influe  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbInst Phys; Indian Assoc Cutivat ScicOCT  a443-4480 v2563 a<p>Interactions between oxygen and Pd-surfaces have important implications, especially towards oxidation reactions, and influence of subsurface oxygen to oxidation reactions is the focus of the present study. In our efforts to understand the above aspects, CO oxidation reactions have been carried out with mixed molecular beam (MB), consisting CO and O(2), on Pd(1 1 1) surfaces under a wide variety of conditions (T = 400-900 K, CO: O(2) = 7: 1 to 1: 10). A new aspect of the above reaction observed in the transient kinetics regime is the evidence for oxygen diffusion into Pd subsurface layers, and its significant influence towards CO oxidation at high temperatures (&gt;= 600 K). Interesting information derived from the above studies is the necessity to fill up the subsurface layers with oxygen atoms to a threshold coverage (theta(O-sub)), above which the reactive CO adsorption occurs on the surface and simultaneous CO(2) production begins. There is also a significant time delay (G) observed between the onset of oxygen adsorption and CO adsorption (and CO(2) production). Above studies suggest an electronic decoupling of oxygen covered surface and subsurface layers, which is slightly oxidized, from the metallic bulk, which induces CO adsorption at high temperatures and simultaneous oxidation to CO(2). (C) 2009 Elsevier B.V. All rights reserved.</p>10aElectronic decoupling10aheterogeneous catalysis10amolecular beam10aOxidation10aPd(111)10aSubsurface diffusion1 aThirunavukkarasu, Kandasamy1 aNagarajan, Sankaranarayanan1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/electronic-decoupling-surface-layers-bulk-and-its-influence-oxidation-catalysis-molecular-001619nas a2200229   4500008004100000022001400041245012400055210006900179260007700248300001000325490000600335520074600341653001501087653001301102653001401115653001401129653002101143100003001164700003201194700003201226856013101258       2009                        eng d  a1861-472800aKinetic evidence for the influence of subsurface oxygen on palladium surfaces towards CO oxidation at high temperatures0 aKinetic evidence for the influence of subsurface oxygen on palla  aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcOCT  a74-800 v43 a<p>Transient state kinetics of the catalytic oxidation of CO with 0, on Pd-surfaces has been measured under isothermal conditions by using a molecular beam approach. Systematic studies were carried out as a function of reaction temperature and CO+O(2) composition. With sufficient kinetic evidence, we have demonstrated the positive influence of subsurface oxygen towards CO-adsorption and oxidation to CO, at high temperatures (600-900 K) on Pd-surfaces, and the likely electronic nature of the surface changes with oxygen in the subsurface. These studies also provide a direct proof for CO-adsorption with a significantly reactive sticking coefficient at high temperatures on Pd-surfaces exhibiting a significant subsurface O-coverage.</p>10aAdsorption10akinetics10aOxidation10aPalladium10asurface analysis1 aGopinath, Chinnakonda, S.1 aThirunavukkarasu, Kandasamy1 aNagarajan, Sankaranarayanan  uhttps://library.ncl.res.in/content/kinetic-evidence-influence-subsurface-oxygen-palladium-surfaces-towards-co-oxidation-high-001866nas a2200229   4500008004100000022001400041245008200055210006900137260007700206300001200283490000600295520102500301653002801326653001401354653003101368653002201399653002501421100003001446700001501476700003201491856011301523       2015                        eng d  a1867-388000aCan we shift and/or broaden the catalysis regime towards ambient temperature?0 aCan we shift andor broaden the catalysis regime towards ambient   aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a588-5940 v73 a<p>An attempt was made to shift the temperature regime of oxidation catalysis towards ambient temperatures by employing surface modification (SM) as a handle. Systematic SM of Pd(111) was performed by O-atom diffusion into the subsurfaces. Virgin and modified Pd(111) catalysts were evaluated for CO oxidation. Typical CO poisoning observed on virgin surfaces was partially lifted, and ambient CO oxidation was observed on the modified surfaces. CO oxidation was followed by the molecular beam method and near-ambient pressure (NAP) photoelectron spectroscopy under different pressure regimes. UV valence band spectral analysis of the SM and the CO+O-2 reaction on modified Pd(111) surfaces under NAP conditions demonstrated changes in the electronic structures of the surfaces with a change in surface potential by 0.35eV and directly probed CO2 formation under the reaction conditions. Supported metal catalysts may be subjected to SM and evaluated for a shift in the catalysis regime for many different reactions.</p>10aheterogeneous catalysis10aOxidation10aphotoelectron spectroscopy10asurface chemistry10asurface modification1 aGopinath, Chinnakonda, S.1 aRoy, Kanak1 aNagarajan, Sankaranarayanan  uhttps://library.ncl.res.in/content/can-we-shift-andor-broaden-catalysis-regime-towards-ambient-temperature-0