01836nas a2200169   4500008004100000022001400041245019100055210006900246260007100315300001400386490000800400520106600408100001501474700001801489700003001507856012901537       2013                        eng d  a1932-744700aDesign and performance aspects of a custom-built ambient pressure photoelectron spectrometer toward bridging the pressure gap: oxidation of Cu, Ag, and Au surfaces at 1 mbar O-2 pressure0 aDesign and performance aspects of a custombuilt ambient pressure  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a4717-47260 v1173 a<p>The critical features of a custom-built laboratory version ambient pressure photoelectron spectrometer (Lab-APPES) are presented. A double front cone differential pumping arrangement and an aperture free design employed in the electrostatic lens regime improve the data collection and data quality. In contrast to the conventional X-ray photoelectron spectrometers (XPS) operating at ultrahigh vacuum (UHV), it is possible to explore the electronic structure of solid surfaces under working conditions or closer to working conditions with Lab-APPES. Especially surface-dependent phenomena can be explored up to 1 mbar pressure and up to 873 K by conventional heating methods and at least up to 1273 K by a laser heating method. Simultaneous XPS and reaction kinetic measurements on solid surfaces make the Lab-APPES an important tool to measure the dynamic electronic structure changes on material surfaces under reaction conditions. The interaction of O-2 with polycrystalline foils of Cu, Ag, and Au from UHV to 1 mbar and up to 773 K has been studied.</p>1 aRoy, Kanak1 aVinod, C., P.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/design-and-performance-aspects-custom-built-ambient-pressure-photoelectron-spectrometer-001035nas a2200193   4500008004100000022001400041245013700055210006900192260011000261300001200371490000700383520021200390100002500602700002200627700001900649700001500668700003000683856012800713       2014                        eng d  a1359-734500aChemically doped perylene diimide lamellae based field effect transistor with low operating voltage and high charge carrier mobility0 aChemically doped perylene diimide lamellae based field effect tr  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT  a326-3280 v503 a<p>Chemical doping of an electron transporter results in the formation of a radical anion containing semiconductor which showed high electron mobility (13 cm(2) V-1 s(-1)) at low operating voltage (1 V).</p>1 aArulkashmir, Arulraj1 aJain, Bhanprakash1 aJohn, Jino, C.1 aRoy, Kanak1 aKrishnamoorthy, Kothandam  uhttps://library.ncl.res.in/content/chemically-doped-perylene-diimide-lamellae-based-field-effect-transistor-low-operating-002674nas a2200265   4500008004100000022001400041245011200055210006900167260007700236300001200313490000600325520169700331653002802028653001302056653002502069653001902094653002002113100003302133700002502166700001602191700001502207700002702222700003002249856012902279       2014                        eng d  a1867-388000aDisordered mesoporous TiO2-xNx+Nano-Au: an electronically integrated nanocomposite for solar H-2 generation0 aDisordered mesoporous TiO2xNxNanoAu an electronically integrated  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a522-5300 v63 a<p>We report on H-2 generation by photocatalysis driven by simulated white light by electronically integrated Au nanoparticles with multifunctional, disordered mesoporous TiO2-xNx (Au-NT) nanocomposites. Solar H-2 generation (1.5 mmolh(-1)g(-1)) from aqueous methanol has been demonstrated with Au-NT nanocomposites. The water splitting activity of Au-NT is attributed to the 21.1 ps lifetime of charge carriers observed from fluorescence lifetime measurements, which indicates a high electron-injection efficiency from nano-Au to the conduction band of TiO2, and hence charge separation as well as utilization. This is directly supported by the observation of a high photoluminescence emission intensity with Au-NT that highlights the energy transfer from nano-Au to TiO2. The p-n heterojunction observed between the Au (001) and TiO2 (101) facets helps to-wards the higher charge separation and their utilization. A low mesochannel depth (&lt; 10 nm) associated with disordered mesoporous TiO2-xNx helps the charge carriers to move towards the surface for redox reactions and hence charge utilization. Visible-light absorption, as a result of the surface plasmon resonance of nano-Au, is observed in a broad range between 500 and 750 nm, which helps in harvesting visible-light photons. Finally, electronically integrated nano-Au with TiO2-xNx in Au-NT is evident from Raman and X-ray photoelectron spectroscopy measurements. All of these factors help to achieve a high rate of H-2 production. It is likely that a higher rate of H-2 production than that reported here is feasible by strategically locating Au clusters in porous TiO2 to generate hot spots through electronic integration.</p>10aheterogeneous catalysis10aHydrogen10amesoporous materials10aphotochemistry10awater splitting1 aSivaranjani, Kumarsrinivasan1 aRajaambal, Sivaraman1 aDas, Tanmay1 aRoy, Kanak1 aBhattacharyya, Somnath1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/disordered-mesoporous-tio2-xnxnano-au-electronically-integrated-nanocomposite-solar-h-2-002799nas a2200253   4500008004100000022001400041245015200055210006900207260007100276300001400347490000600361520184700367653002102214653002002235653001002255653002802265653002102293653002302314100001602337700001502353700003002368700001502398856013202413       2014                        eng d  a1944-824400aFacile single-step synthesis of nitrogen-doped reduced graphene oxide-Mn3O4 hybrid functional material for the electrocatalytic reduction of oxygen0 aFacile singlestep synthesis of nitrogendoped reduced graphene ox  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a2692-26990 v63 a<p>Development of efficient electrocatalyst based on non-precious metal that favors the four-electron pathway for the reduction of oxygen in alkaline fuel cell is a challenging task. Herein, we demonstrate a new facile route for the synthesis of hybrid functional electrocatalyst based on nitrogen-doped reduced graphene oxide (N-rGO) and Mn3O4 with pronounced electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline solution. The synthesis involves one-step in situ reduction of both graphene oxide (GO) and Mn(VII), growth of Mn3O4 nanocrystals and nitrogen doping onto the carbon framework using a single reducing agent, hydrazine. The X-ray photoelectron (XPS), Raman and FTIR spectral, and X-ray diffraction measurements confirm the reduction of GO and growth of nanosized Mn3O4. The XPS profile reveals that N-rGO has pyridinic (40%), pyrrolic (53%), and pyridine N oxide (7%) types of nitrogen. The Mn3O4 nanoparticles are single crystalline and randomly distributed over the wrinkled N-rGO sheets. The hybrid material has excellent ORR activity and it favors the 4-electron pathway for the reduction of oxygen. The electrocatalytic performance of the hybrid catalyst is superior to the N-rGO, free Mn3O4 and their physical mixture. The hybrid material shows an onset potential of -0.075 V, which is 60-225 mV less negative than that of the other catalyst tested. It has excellent methanol tolerance and high durability. The catalytic current density achieved with the hybrid material at 0.1 mg cm(-2) is almost equivalent to that of the commercial Pt/C (10%). The synergistic effect of N-rGO and Mn3O4 enhances the overall performance of the hybrid catalyst. The nitrogen in N-rGO is considered to be at the interface to bridge the rGO framework and Mn3O4 nanoparticles and facilitates the electron transfer.</p>10aelectrocatalysis10ahybrid material10aMn3O410anitrogen-doped graphene10aoxygen reduction10asynergistic effect1 aBag, Sourav1 aRoy, Kanak1 aGopinath, Chinnakonda, S.1 aRaj, Retna  uhttps://library.ncl.res.in/content/facile-single-step-synthesis-nitrogen-doped-reduced-graphene-oxide-mn3o4-hybrid-functional-001608nas a2200217   4500008004100000022001400041245010200055210006900157260007700226300001200303490000600315520081200321653002801133653001301161653001101174653001401185653002201199100001501221700003001236856012401266       2014                        eng d  a1867-388000aNOx reduction at near ambient temperatures and under lean-burn conditions on modified pd surfaces0 aNOx reduction at near ambient temperatures and under leanburn co  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a531-5370 v63 a<p>Palladium surfaces that are modified with O atoms in the subsurface broaden the NO reduction temperature regime up to 325 K with O-2-rich NO+H-2+O-2 compositions. Compared to virgin Pd surfaces, up to 150% higher deNO(x) catalytic activity was observed with modified Pd surfaces at the reaction maximum. Molecular beam instrument and ambient-pressure photoelectron spectroscopy were employed to follow the kinetic and surface changes. These results open up a possibility to realize the cold-start reduction of NOx (deNO(x)). DeNO(x) activity reported in the literature with supported Pd catalysts after a simple calcination in air compares well with our present observations. Surface modification is likely to demonstrate a high potential for other catalytic reactions at relatively low temperatures.</p>10aheterogeneous catalysis10anitrogen10aoxygen10aPalladium10asurface chemistry1 aRoy, Kanak1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/nox-reduction-near-ambient-temperatures-and-under-lean-burn-conditions-modified-pd-002870nas a2200265   4500008004100000022001400041245014500055210006900200260007100269300001400340490000600354520191100360653001202271653002802283653001302311653001402324653001902338653001702357653001402374653002502388100001502413700001602428700003002444856013002474       2014                        eng d  a2155-543500aTowards a sustainable and near ambient DeNO(x) under lean burn conditions: a revisit to no reduction on virgin and modified pd(111) surfaces0 aTowards a sustainable and near ambient DeNOx under lean burn con  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a1801-18110 v43 a<p>Catalytic conversion of NO in the presence of H-2 and O-2 has been studied on Pd(111) surfaces, by using a molecular beam instrument with mass spectrometry detection, as a function of temperature and reactants composition. N-2 and H2O are the major products observed, along with NH3 and N2O minor products under all conditions studied. Particular attention has been paid to the influence of O-2 addition toward NO dissociation. Although O-2-rich compositions were found to inhibit the deNO(x) activity of the Pd catalyst, some enhancement in NO reduction to N-2 was also observed up to a certain O-2 content. The reason for this behavior was determined to be the effective consumption of the H-2 in the mixture by the added O-2 and O atoms from NO dissociation. NO was proven to compete favorably against O-2 for the consumption of H-2, especially &lt;= 550 K, to produce N-2 and H2O. Compared with other elementary reaction steps, a slow decay observed with the 2H + 0 -&gt; H2O step under SS beam oscillation conditions demonstrates its contribution to the rate-limiting nature of the overall reaction. Pd(111) surfaces modified with O atoms in the subsurface (Md-Pd(111)) induces steady-state NO reduction at near-ambient temperatures (325 K) and opens up a possibility to achieve room temperature emission control. A 50% increase in the reaction rates was observed at the reaction maximum on Md-Pd(111), as compared with virgin surfaces. Oxygen adsorption is severely limited below 400 K, and effective NO + H-2 reaction occurs on Md-Pd(111) surfaces. Valence band photoemission with a UV light source (He I) under different oxygen pressures with APPES clearly identified the characteristics of the Md-Pd(111) surfaces and PdO. The electron-deficient or cationic nature of Md-Pd(111) surfaces enhances the NO dissociation and inhibits oxygen chemisorption &lt;= 400 K under lean-burn conditions.</p>10adeNO(x)10aheterogeneous catalysis10aHydrogen10alean burn10amolecular beam10anitric oxide10aPalladium10asurface modification1 aRoy, Kanak1 aJain, Ruchi1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/towards-sustainable-and-near-ambient-denox-under-lean-burn-conditions-revisit-no-reduction01625nas a2200157   4500008004100000022001400041245012600055210006900181260007100250300001400321490000700335520095400342100001501296700003001311856012601341       2014                        eng d  a0003-270000aUV photoelectron spectroscopy at near ambient pressures: mapping valence band electronic structure changes from Cu to CuO0 aUV photoelectron spectroscopy at near ambient pressures mapping   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR  a3683-36870 v863 a<p>Valence band (VB) changes and hence electronic structure evolution was directly observed with low kinetic energy (KE) electrons at near ambient pressure (NAP) conditions with He I photon source in a custom built laboratory ambient pressure photoelectron spectrometer (Lab-APPES). Polycrystalline Cu surfaces were gradually oxidized in O-2 to Cu2O, to a mixture of Cu2O + CuO, and finally to CuO between 300 and 625 K and at NAP. Typical VB features for Cu, Cu2O, and CuO were observed, and the results corroborate well with core level and Auger spectral changes. High mean free path associated with low KE electrons, very low or no inelastic scattering, and effective pumping and the design of electrostatic lens regime help to minimize the electron attenuation at NAP conditions. The present results extend the capabilities of the APPES tool to explore the in situ evolution of electronic structure of materials at NAP and high temperatures.</p>1 aRoy, Kanak1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/uv-photoelectron-spectroscopy-near-ambient-pressures-mapping-valence-band-electronic-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-002106nas a2200193   4500008004100000245008300041210006900124260000800193300000900201490000600210520145500216100001801671700002301689700002601712700001501738700001801753700003001771856011101801       2016                        eng d00aPorous thin films towards bridging the material gap in heterogeneous catalysis0 aPorous thin films towards bridging the material gap in heterogen  cMAR  a1-120 v23 a<p>An attempt has been made to bridge the material gap, existing between ideal single crystals and real-world powder nanocatalyst employed in surface science and heterogeneous catalysis, respectively. Simple wet chemical method (sol–gel and spin-coating deposition) has been applied to make continuous Ce1 − xZrxO2 (x = 0–1) (CZ) thin films with uniform thickness (~40 nm) and smooth surface characteristics. Uniform thickness and surface smoothness of the films over a large area was supported by a variety of measurements. Molecular beam (MB) studies of O2 adsorption on CZ surfaces reveals the oxygen storage capacity (OSC), and sticking coefficient increases from 400 to 800 K. Porous nature of Ce-rich CZ compositions enhances O2 adsorption and OSC, predominantly due to O-diffusion and redox nature, even at 400 K. A good correlation exists between MB measurements made on CZ films for oxygen adsorption, and OSC, and ambient pressure CO oxidation on powder form of CZ; this demonstrates the large potential to bridge the material gap. CZ was particularly chosen as a model system for the present studies, since it has been well-studied and a correlation between surface science properties made on thin films and catalysis on powder CZ materials could be a litmus test. Ambient catalysis on ceria-zirconia nanocatalyst correlates well with surface properties measured through molecular beam on thinfilm and close the material gap.</p>1 aDubey, Anjani1 aKolekar, Sadhu, K.1 aGnanakumar, Edwin, S.1 aRoy, Kanak1 aVinod, C., P.1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/porous-thin-films-towards-bridging-material-gap-heterogeneous-catalysis01572nas a2200181   4500008004100000245010500041210006900146260000800215300001400223490000700237520090200244100001501146700001601161700002701177700002901204700003001233856012701263       2016                        eng d00aThree way catalytic converter reactions aspects at near ambient temperatures on modified pd-surfaces0 aThree way catalytic converter reactions aspects at near ambient   cOCT  a1363-13690 v193 a<p>The dissolution of oxygen in palladium plays an important role in palladium catalysis. The present study shows that the surface modification (SM) due to the dissolution of atomic oxygen into the subsurfaces of palladium can be used as a control to tune its catalytic activity. CO oxidation and NO + H-2 + O-2 reaction was separately carried out on metallic Pd and on surface modified Pd using a molecular beam instrument and the results were compared. The metallic Pd does not show activity below 400 K for both reactions, whereas the SM-Pd shows activity at near-ambient temperatures. The electronic change due to SM was investigated using ambient pressure photoelectron spectroscopy, and the investigation clearly shows the effect of subsurface oxygen in the ambient temperature activity of palladium. (C) 2016 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.</p>1 aRoy, Kanak1 aJain, Ruchi1 aGhosalya, Manoj, Kumar1 aReddy, Kasala, Prabhakar1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/three-way-catalytic-converter-reactions-aspects-near-ambient-temperatures-modified-pd-002198nas a2200241   4500008004100000022001200041245012300053210006900176260000800245300000700253490000800260520135300268653002501621653001601646653002801662653002001690100002701710700002901737700001601766700001501782700003001797856012901827       2018                        eng d  a974362600aSubtle interaction between Ag and O 2 : a near ambient pressure UV photoelectron spectroscopy (NAP-UPS) investigations0 aSubtle interaction between Ag and O 2 a near ambient pressure UV  cMAR  a300 v1303 aThe Ag-O2 interaction, which is at the center-stage of Ag-catalyzed partial oxidation reactions, is
studied with NAP-UPS up to 0.2 mbar O2 pressure between 295 and 550 K. Three temperature regimes were
identified for distinct Ag-O2 interaction, which are (a) 295–390 K, where mainly dissociative chemisorption of
O2 happens, (b) 390–450 K, where diffusion of O-atoms into the sub-surfaces of Ag is prominent, and (c) >450
K, where metastable oxide forms on polycrystalline Ag surfaces. The work function (WF) of Ag changed from
4.95 (≤390 K) to 5.30 eV (390–450 K), and then to 5.7 eV (≥450 K) at 0.1 mbar O2 pressure. Oxygen population
in the sub-surfaces imparts crucial modifications to Ag at 390–450 K; it makes the surface to be electron-deficient
that relates to the change in the WF of Ag and facilitates the formation of space charge layer on Ag surface.
Oxygen adsorbed on such modified Ag-surfaces is electrophilic in nature, and this appears at a higher binding
energy in core level XPS than the chemisorbed oxygen on metallic Ag. This is supported by angle-dependent
NAP-XPS studies. The subsurface population of oxygen in Ag no longer persists at >410 K when the O2 supply
is removed. A high ratio of antibonding/bonding O 2p bands suggests the unique silver-oxygen interaction under
the measurement conditions.10aElectronic Structure10aepoxidation10aheterogeneous catalysis10aSurface Science1 aGhosalya, Manoj, Kumar1 aReddy, Kasala, Prabhakar1 aJain, Ruchi1 aRoy, Kanak1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/subtle-interaction-between-ag-and-o-2-near-ambient-pressure-uv-photoelectron-spectroscopy