01144nas a2200229 4500008004100000022001400041245006200055210006100117260010600178300001400284490000700298520033200305653003200637653000800669653002100677653004300698100001900741700002300760700001600783700001900799856009600818 2014 eng d a0040-403900aChemoselective deprotection of N-allylic amines using DDQ0 aChemoselective deprotection of Nallylic amines using DDQ aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC a7172-71760 v553 a

A highly chemoselective and simple method for the deprotection of N-allylic amines using DDQ has been developed. The use of DDQ in dichloromethane-water provides a mild and efficient one-step deallylation of a wide variety of orthogonally protected tertiary amine derivatives. (C) 2014 Elsevier Ltd. All rights reserved.

10aChemoselective deprotection10aDDQ10aN-Allylic amines10aOrthogonally protected tertiary amines1 aKumar, Pradeep1 aCherian, Shijo, K.1 aJain, Ruchi1 aShow, Krishanu uhttps://library.ncl.res.in/content/chemoselective-deprotection-n-allylic-amines-using-ddq-001590nas a2200217 4500008004100000022001400041245006700055210006500122260011000187300001400297490000700311520080700318100002201125700001801147700002601165700002201191700001601213700003001229700002001259856009301279 2014 eng d a1144-054600aFacile method for the synthesis of Co-core Au-shell nanohybrid0 aFacile method for the synthesis of Cocore Aushell nanohybrid aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a4107-41140 v383 a

Heterostructured Co-Au core-shell nanoparticles have been synthesized by reducing AuCl4- ions on cobalt nanoparticles after a minor but effective modification of cobalt surface by an amine. The core shell morphology is emphatically confirmed by thorough investigation through UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopic analysis (TEM). The chemical composition and topography were determined using STEM-HAADF analysis and EFTEM imaging. Fourier transform infrared (FTIR) spectroscopy confirms the surface modification of Co nanoparticles and the interactions involved between the ligands and the core and shell metals at various steps of the synthetic process. The magnetic properties confirm the material to be superparamagnetic in nature.

1 aSardar, Debasmita1 aNeogi, S., K.1 aBandyopadhyay, Sanjoy1 aSatpati, Biswarup1 aJain, Ruchi1 aGopinath, Chinnakonda, S.1 aBala, Tanushree uhttps://library.ncl.res.in/content/facile-method-synthesis-co-core-au-shell-nanohybrid-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

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 <= 550 K, to produce N-2 and H2O. Compared with other elementary reaction steps, a slow decay observed with the 2H + 0 -> 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 <= 400 K under lean-burn conditions.

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-reduction02032nas a2200241 4500008004100000022001400041245008300055210006900138260011000207300001400317490000700331520114000338100002201478700001801500700002601518700002201544700001801566700002101584700001601605700003001621700002001651856011901671 2015 eng d a1144-054600aMultifaceted core-shell nanoparticles: superparamagnetism and biocompatibility0 aMultifaceted coreshell nanoparticles superparamagnetism and bioc aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG a8513-85210 v393 a

NicoreAgshell nanoparticles were synthesized by redox transmetallation reaction. Reduction potential match was encouraging to attempt the synthesis of the NicoreAushell system too. However, it could be achieved only after an effective surface modification on the Ni-core. Thorough characterization (UV-Vis spectroscopy, fluorescence spectroscopy, XRD, XPS, FTIR, TEM, and EDX) proved the necessity of surface modification and the success of synthesis of both types of core-shell structures. The chemical composition and topography were determined using STEM-HAADF analysis and EFTEM imaging. Fourier transform infrared (FTIR) spectroscopy confirmed the surface modification of Ni nanoparticles and the interactions involved between the ligands and metals (in the core and/or the shell) at various steps of the synthetic process. Even after the formation of the noble metal shell, the magnetic core was found to retain its superparamagnetic nature. In addition, the Au-shell protected the core from aerial oxidation and decreased toxicity as compared to pristine Ni nanoparticles as observed by MTT assay on normal cells (PBMCs).

1 aSardar, Debasmita1 aNeogi, S., K.1 aBandyopadhyay, Sanjoy1 aSatpati, Biswarup1 aAhir, Manisha1 aAdhikary, Arghya1 aJain, Ruchi1 aGopinath, Chinnakonda, S.1 aBala, Tanushree uhttps://library.ncl.res.in/content/multifaceted-core-shell-nanoparticles-superparamagnetism-and-biocompatibility-002572nas a2200181 4500008004100000022001400041245011600055210006900171260011000240300001400350490000600364520180000370100001602170700001802186700002702204700003002231856012902261 2016 eng d a2044-475300aGas-solid interaction of H-2-Ce0.95Zr0.05O2: new insights into surface participation in heterogeneous catalysis0 aGassolid interaction of H2Ce095Zr005O2 new insights into surface aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a1746-17560 v63 a

A direct interaction between a reduction medium (H-2) and a Ce0.95Zr0.05O2 (CZ) solid surface was explored through ambient pressure photoelectron spectroscopy (APPES), with conventional X-ray and He-I photon sources, in H-2 atmosphere up to 0.1 mbar pressure and 773 K. A porous CZ thin film was prepared by a combination of sol-gel and spin-coating methods, and was employed to understand the redox nature of ceria under reduction conditions. The maximum of 45% Ce3+ along with the corresponding oxygen vacancy was observed due to reduction. An unprecedented decrease in the valence band (VB) energy up to 1.4 eV was observed on reduction along with a narrowing of VB. The highest occupied energy band derived from Ce 4f also shifts closer to E-F. H-2 molecular vibration observed in VB-APPES was employed as a probe to explore the surface potential changes along with the dynamic change in the nature of the surface under reduction conditions. The surface potential decreases by 0.27 eV up to 673 K, and then it reverts by 0.24 eV on further reduction at 773 K for different reasons. Further, an enhancement in the Ce 5d-O 2p interaction occurs at the expense of the Ce 4f-O 2p interaction under the above reduction conditions. Vacuum annealing and H-2 reduction after that show significantly more VB shift and enhanced reduction than H-2 reduction alone. Although Ce reduction occurs on high temperature vacuum annealing of CZ, a significantly lower amount of oxygen vacancies appears. This study shows the dynamic changes in the nature of the surface due to a gas (H-2)-solid (CZ) interaction and ensuing electronic structure changes that influence heterogeneous catalysis. It also underscores the necessity to study the catalytic materials under in situ conditions or closer to that.

1 aJain, Ruchi1 aDubey, Anjani1 aGhosalya, Manoj, Kumar1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/gas-solid-interaction-h-2-ce095zr005o2-new-insights-surface-participation-heterogeneous-001572nas 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

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.

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-001799nas a2200181 4500008004100000022001400041245012100055210006900176260000900245300001400254490000600268520112600274100002601400700001601426700003001442700001801472856012701490 2017 eng d a2044-475300aDiverse reactivity trends of Ni surfaces in Au@Ni core-shell nanoparticles probed by near ambient pressure (NAP) XPS0 aDiverse reactivity trends of Ni surfaces in AuNi coreshell nanop cOCT  a4489-44980 v73 aA mild temperature sequential reduction method in aqueous medium is reported for the synthesis of Au@Ni nanoparticles with a core-shell morphology. The nickel shell thickness with a gold core in the nanostructure can be tuned from 2 nm up to about 10 nm. Near ambient pressure XPS (NAPXPS) studies under oxygen atmosphere show that Au-80@Ni-20 with an extremely thin nickel shell (similar to 2 nm) follows a distinctly different decomposition pathway of metastable Ni(OOH) species compared to those with larger shell thickness which behave more like individual nickel surfaces. Thus, Ni(OOH) on Au-80@Ni-20 decomposes to metallic Ni at 100 degrees C and is found to resist oxidation at 0.1 mbar oxygen at this temperature. Those with a larger nickel shell thickness behave more like monometallic Ni in terms of their decomposition and oxidation properties. The Au@Ni system with an ultra thin metallic nickel overlayer (2 nm) shows high catalytic activity and selectivity for phenylacetylene hydrogenation under mild conditions which outweighs their monometallic counterparts and those with higher nickel shell thickness.1 aBharathan, Vysakh, A.1 aJain, Ruchi1 aGopinath, Chinnakonda, S.1 aVinod, C., P. uhttps://library.ncl.res.in/content/diverse-reactivity-trends-ni-surfaces-auni-core-shell-nanoparticles-probed-near-ambient02357nas a2200181 4500008004100000022001400041245011900055210006900174260000800243300001600251490000800267520167700275100002901952700001601981700002701997700003002024856012102054 2017 eng d a1932-744700aMetallic cobalt to spinel Co3O4-electronic structure evolution by near-ambient pressure photoelectron spectroscopy0 aMetallic cobalt to spinel Co3O4electronic structure evolution by cOCT a21472-214810 v1213 a

In the present study, valence band (VB) and core level photoelectron spectroscopy was carried out to investigate the electronic structural changes from polycrystalline Co to spinel Co3O4, via CoO at near ambient pressures (NAP; similar to 0.1). O-2 Co and H-2-CoOx gas solid oxidative and reductive interactions, respectively, have been explored with UV photons (He I) or low kinetic energy electrons (<= 16 eV) under NAP conditions. Typical VB features of Co metal, CoOx Co3O4, and a mixed phase between any two adjacent features were observed and well corroborated with core level changes. Very significant and characteristic changes were observed with Co 3d features in the VB for each stage from Co oxidation to Co3O4 as well as Co3O4 reduction to CoOx Co(3O)4 and CoO can be reversibly obtained by alternating the conditions between 0.1 mbar of H-2 at 650 K and 0.1 mbar of O 2 at 400 K, respectively. A meaningful correlation is observed between the changes in work function with cation oxidation state; small changes in the stoichiometry can strongly influence the shift in Fermi level and changes in work function under NAP conditions. Reversible work function changes are observed at a constant BE (similar to 5 ev) between oxidation and reduction conditions. While the O 2 p derived feature for CoOx was observed at throughout the redox conditions, the Co 3d band and molecular oxygen or hydrogen vibration feature shifts significantly underscoring the physicochemical changes, such as charge transfer energy and hence changes in satellite intensity. The peak close to E-F originated from the 3d(6)L final state of the octahedral Co3+ 3d band of Co3O4.

1 aReddy, Kasala, Prabhakar1 aJain, Ruchi1 aGhosalya, Manoj, Kumar1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/metallic-cobalt-spinel-co3o4-electronic-structure-evolution-near-ambient-pressure01720nas a2200205 4500008004100000245013500041210006900176260000800245520093500253100002201188700002401210700002001234700001901254700001801273700002601291700001601317700003001333700002001363856013101383 2017 eng d00aMultiple functionalities of Ni nanoparticles embedded in carboxymethyl guar gum polymer: catalytic activity and superparamagnetism0 aMultiple functionalities of Ni nanoparticles embedded in carboxy cJAN3 aComposites comprising of metallic nanoparticles in polymer matrices have allured significant importance due to multifunctionalities. Here a simple protocol has been described to embed Ni nanoparticles in carboxymethyl guar gum (CMGG) polymer. The composite formation helps in the stabilization of Ni nanoparticles which are otherwise prone towards aerial oxidation. Further the nanoparticles retain their superparamagnetic nature and catalytic capacity. Ni-Polymer composite catalyses the reduction of 4-Nitrophenol to 4-Aminophenol very efficiently in presence of NaBH4, attaining a complete conversion under some experimental conditions. Ni-Polymer composite is well characterized using UV–vis spectroscopy, FTIR, XPS, powder XRD, TGA, SEM and TEM. A detailed magnetic measurement using superconducting quantum interference device-vibrating sample magnetometer (SQUID-VSM) reveals superparamagnetic behaviour of the composite.1 aSardar, Debasmita1 aSengupta, Manideepa1 aBordoloi, Ankur1 aAhmed, Md., A.1 aNeogi, S., K.1 aBandyopadhyay, Sanjoy1 aJain, Ruchi1 aGopinath, Chinnakonda, S.1 aBala, Tanushree uhttps://library.ncl.res.in/content/multiple-functionalities-ni-nanoparticles-embedded-carboxymethyl-guar-gum-polymer-catalytic02884nas a2200301 4500008004100000022001400041245016300055210006900218260000800287300001800295490000800313520181300321653002402134653002002158653001402178653001702192653001202209653002902221653001902250653002802269653003602297653001502333100001602348700002902364700002702393700003002420856013202450 2017 eng d a1932-744700aWater mediated deactivation of Co3O4 naonrods catalyst for CO oxidation and resumption of activity at and above 373 K: electronic structural aspects by NAPPES0 aWater mediated deactivation of Co3O4 naonrods catalyst for CO ox cSEP a20296–203050 v1213 a

The catalytic activity of the Co3O4 nanorods (NRs) for the CO oxidation reaction and the effect of water on the catalytic reaction have been explored with near-ambient pressure photoelectron spectroscopy (NAPPES) and mass spectral analysis. Comparative NAPPES studies have been employed to understand the elucidation of the catalytic reaction pathway and the evolution of various surface species. The results confirm the suppression of the CO oxidation activity on the Co3O4 NRs in the presence of water vapor. Various type of surface species, such as CO(ads), hydroxyl, carbonate, formate, are found to be present on the catalyst surface depending on the reaction conditions. Vibrational features of CO, O-2, and CO, were observed and shift in binding energy of these features under the reaction conditions directly suggests a change in work function of the catalyst surface. Under dry conditions, CO couples with labile 0 atoms to form CO2; however, under wet conditions, CO predominantly interacts with surface OH groups resulting in the formation of carbonate and formate intermediates. In situ studies of oxidation of CO on Co3O4 shows that CO oxidation depends not only on surface Co3+ concentration but also influenced by Co-3/Co' ratio on the catalyst surface. The carbonate was found to be a reaction inhibitor at room temperature; however, it acts as an active intermediate at 375 K and above. Above the boiling point of water, Co3O4 NR surfaces begin to show the oxidation activity even in the presence of water vapor. The intrinsic role of intermediate species was used to derive a possible reaction mechanism under different reaction conditions.

10aAmbinent-temprature10acarbon monoxide10aGas Shift10aH Activation10aIn-situ10aLow-temprature oxidation10aMolecular-beam10aPerformance enhancement10aRay Photoelectron-Spectroscopyu10aThin-films1 aJain, Ruchi1 aReddy, Kasala, Prabhakar1 aGhosalya, Manoj, Kumar1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/water-mediated-deactivation-co3o4-naonrods-catalyst-co-oxidation-and-resumption-activity-and02571nas a2200157 4500008004100000022001400041245017100055210006900226260000900295300001600304490000700320520191700327100001602244700003002260856012302290 2018 eng d a1944-824400aNew strategy toward a dual functional nanocatalyst at ambient conditions: influence of the Pd-Co interface in the catalytic activity of Pd@Co core-shell nanoparticles0 aNew strategy toward a dual functional nanocatalyst at ambient co cDEC  a41268-412780 v103 a

Bimetallic nanostructures with a combination of noble and nonnoble metals hold promise for improving catalyst activity and selectivity. Here, we report the synthesis of Pd@Co (PC) core shell morphology nanoparticles with three different ratios of palladium (Pd) and cobalt (Co), and a possibility to fine tune the ratio of core and shell thickness. PC exhibits superior and selective hydrogenation as well as oxidation catalytic activity at ambient or near-ambient conditions. Various characterization techniques have been employed to confirm the core shell morphology. Without any pre-treatment or activation, fresh catalysts with different Pd to Co ratios, that is, 2:1, 1:1, and 1:2, were subjected to olefin (phenylacetylene) hydrogenation and oxidation (styrene to styrene oxide) reaction. The catalytic activity results demonstrate that the 1:1 ratio of Pd/Co is the most active composition for controlled and stepwise reduction of phenyl acetylene to styrene and then to ethyl benzene; 1:1 Pd/Co shows 100% styrene conversion in 30 min. with an order of magnitude higher turnover frequency than other catalysts. The 1:1 PC ratio is also the most active composition for selective oxidation of styrene to styrene oxide. NAPXPS (near-ambient pressure XPS) results show that the active sites for catalytic hydrogenation and oxidation reaction are Co and Co3+, respectively. However, the superior catalytic performance can be attributed to Co (for reduction) or Co3+ (for oxidation), and the Pd Co interface plays a critical role in stabilizing the required functional character. NAPXPS results confirm that the superior catalytic performance can be attributed not only to Co or Co3+, but also to the Pd Co interface. The electronic effect and synergism between Co and Pd helps Co to stabilize in different oxidation states depending on the reaction conditions, and making it a dual functional catalyst.

1 aJain, Ruchi1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/new-strategy-toward-dual-functional-nanocatalyst-ambient-conditions-influence-pd-co02626nas a2200181 4500008004100000022001400041245012400055210006900179260000900248300001400257490000800271520193900279100002702218700001602245700002902261700003002290856012402320 2018 eng d a1932-744700aSilicon oxidation by NAPPES: From dangling bonds to oxygen islands to 2D SiOx layer to the onset of bulk SiO2 formation0 aSilicon oxidation by NAPPES From dangling bonds to oxygen island cMAR  a4331-43380 v1223 a

Valence band and core level photoelectron spectral measurements at near-ambient pressures (NAP; up to 0.5 mbar) were made in the presence of molecular oxygen to explore the various oxidation stages of silicon surfaces. Dangling bonds feature observed on clean Si-surfaces in the valence band at ultrahigh vacuum decreases dramatically due to oxygen adsorption between ambient temperature and up to 400 K at 0.1 mbar of O-2 pressure. The adsorption of oxygen on dangling bonds appears to be localized as islands; this reflects in the surface heterogeneous character and also responsible for the broadening in the oxygen gas phase vibrational features. This is further supported by an increase in the work function and can be correlated to the presence of Hofer (molecular) precursor. When the temperature was increased to 500 K, molecular precursor species dissociates to form Si-=-0 species. This is fully supported by the change in the Si work function as well as from the observation of oxidized Si species from Si 2p core level spectra. At >= 600 K, the Si-=-0 species dissociates to form a uniform 2D oxide layer on the silicon surface, which is characterized by the reappearance of sharp vibration features for gas-phase O-2 molecules. This layer is also quite stable up to 800 K and without any further oxidation in the bulk. On increasing the temperature to 850 K at 0.2 mbar oxygen pressure, bulk Si oxidation begins and the work function increases drastically by 1 eV. An angle-dependent Si 2p spectra recorded map out the presence of elemental Si to Si4+ from bulk to the surface, respectively. A simple model is proposed to show the various stage of silicon oxidation. A continuous change in the work function and electronic states observed due to gas-lattice (O-2-Si) interaction indicates the implications for surface-dependent phenomena, such as heterogeneous catalysis, electrochemistry, 2D layered materials.

1 aGhosalya, Manoj, Kumar1 aJain, Ruchi1 aReddy, Kasala, Prabhakar1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/silicon-oxidation-nappes-dangling-bonds-oxygen-islands-2d-siox-layer-onset-bulk-sio202198nas 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-spectroscopy01300nas a2200205 4500008004100000245017600041210006900217260000800286300001400294490000700308520050000315100002400815700002300839700001600862700002400878700002200902700002400924700001900948856012700967 2018 eng d00aUnravelling the nucleophilicity of buten tides for 1,6-conjugate addition to p-quinone methides: a direct access to diversely substituted butenolide-derived diarylmethanes0 aUnravelling the nucleophilicity of buten tides for 16conjugate a cMAY a2787-27910 v203 aA Lewis acid catalyzed regioselective C-C bond is constructed through beta-addition of deconjugated butenolides with p-quinone methides in a 1,6-conjugate addition manner. Interestingly, Lewis acid catalyzed vinylogous Mukaiyama-Michael reaction of silyloxyfurans with p-QMs proceeds selectively through the alpha or gamma position exclusively. The reaction is mild with broad substrate scope, thus allowing easy access to a wide range of bis-arylated alpha-/beta-/gamma-substituted butenolides.1 aSharma, Brijesh, M.1 aShinde, Dinesh, R.1 aJain, Ruchi1 aBegari, Eeshwaraiah1 aSatbhaiya, Shruti1 aGonnade, Rajesh, G.1 aKumar, Pradeep uhttps://library.ncl.res.in/content/unravelling-nucleophilicity-buten-tides-16-conjugate-addition-p-quinone-methides-direct02249nas a2200157 4500008004100000022001400041245008400055210006900139260000900208300001400217490000700231520169300238100001601931700003001947856011401977 2019 eng d a1477-922600aMorphology-dependent, green, and selective catalytic styrene oxidation on Co3O40 aMorphologydependent green and selective catalytic styrene oxidat cAPR  a4574-45810 v483 a

Despite the great successes in the controlled fabrication of nanomaterials with specific composition and morphology, it is still challenging to have the desired control on the defect sites of catalyst materials. For unfolding the mystery of this aspect, catalytic styrene epoxidation was attempted on spinel Co3O4 with two different morphologies, namely, SNR (nanorods prepared by the solvothermal method with the (110) facet), HNR (nanorods prepared by the hydrothermal methodwith the (111) facet) and NC (nanocubes with the (110) facet) were synthesized and subjected to olefin oxidation with O-2. Even without any catalyst pretreatment, all three Co3O4 catalyst systems were found to be active for selective epoxidation of styrene with O-2 at ambient pressure in the liquid phase. The correlation between catalytic activity and selectivity trend suggests that the reaction is highly structure-sensitive and facile on the (110) facet. Temperature-dependent near ambient pressure X-ray photoelectron spectroscopy (NAPXPS) was carried out at 0.1 mbar O-2 pressure to understand the mechanistic aspects. The distinct catalytic activity of NC (110) and SNR (110) can be attributed to the population of defect sites on the catalyst surface. NC morphology with comparatively fewer defect sites shows high activity and selectivity, suggesting that styrene oxidation on Co3O4 is structure-sensitive; however, unlike metal surfaces, fewer defects are more favourable for catalytic styrene epoxidation due to facile adsorption and activation of the substrate and O-2 on Co3+ sites. The present investigations suggest that surface defects need not necessarily increase catalytic activity.

1 aJain, Ruchi1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/morphology-dependent-green-and-selective-catalytic-styrene-oxidation-co3o401705nas a2200277 4500008004100000022001400041245012400055210006900179260000900248300001100257490000800268520078900276653002101065653001501086653001101101653002001112653002401132653002701156100001901183700001901202700001601221700001601237700003001253700001801283856012601301 2019 eng d a0926-860X00aSurfactant free synthesis of Au@Ni core-shell nanochains in aqueous medium as efficient transfer hydrogenation catalyst0 aSurfactant free synthesis of AuNi coreshell nanochains in aqueou cAPR  a93-1000 v5753 a

A surfactant free aqueous phase synthesis method is reported for the generation of highly lattice mismatched Au@Ni core-shell nanochains without using any expensive and hazardous organic ligands. As synthesised Au@Ni nanochain structures showed high thermal stability and bulk oxidation resistance up to 300 degrees C. In situ near ambient pressure XPS (NAPXPS) analysis has been done for the bare Au@Ni nanochain surfaces under oxygen atmosphere and at different temperatures which showed evidence for the surface oxidation resistance of naked Au@Ni nanochains up to 200 degrees C. Ligand or capping agent free Au@Ni nanochain surfaces are found to be highly active for transfer hydrogenation of acetophenone to 1-phenyl ethanol an important commodity in perfumery industry.

10aAu@Ni nanochains10acore-shell10aNAPXPS10aSurfactant free10asynergistic effects10atransfer hydrogenation1 aVysakh, A., B.1 aShebin, K., J.1 aJain, Ruchi1 aSumanta, P.1 aGopinath, Chinnakonda, S.1 aVinod, C., P. uhttps://library.ncl.res.in/content/surfactant-free-synthesis-auni-core-shell-nanochains-aqueous-medium-efficient-transfer02042nas a2200217 4500008004100000022001400041245012900055210006900184260000900253300001400262490000700276520126400283653002601547653002501573653002801598653001401626653000801640100001601648700003001664856013001694 2020 eng d a1867-388000aElectronic structure evolution of Pd@Co nanocatalysts under oxidation and reduction conditions and preferential CO oxidation0 aElectronic structure evolution of PdCo nanocatalysts under oxida cAUG  a4176-41840 v123 a

Herein, we present the surface electronic structure and morphological evolution under reduction and oxidation conditions for Pd@Co (PC) core-shell nanoparticles with different Pd : Co ratio (PC=2 : 1, 1 : 1 and 1 : 2). Extensive measurements have been made with NAPXPS (near ambient pressure x-ray photoelectron spectroscopy) under oxidising and reducing conditions, and ex-situ HRTEM. It has been demonstrated that PC catalysts are thermally stable towards morphological changes, at least up to 575 K. Nonetheless, it shows a significant surface electronic structure changes under reaction environments, which are highly relevant to heterogeneous catalysis. As expected, high (low) population of metallic (oxidised) Co was observed, while retaining core shell structure under reduction (H(2)and vacuum annealing) environment. Interestingly, the Pd-Co metallic interface helps to overcome the pyrophoric nature of cobalt and stabilised a significant amount of metallic Co at Pd-Co interface even in the presence of 0.1 mbar O(2)up to 575 K. The presence of Pd-Co and Pd-Co@Co(3)O(4)interfaces in reaction environment makes the catalyst dual functional. The proof of concept has been explored in terms of oxidation of CO in the presence of H(2)or O-2.

10aCore-Shell morphology10aElectronic Structure10aheterogeneous catalysis10ainterface10aXPS1 aJain, Ruchi1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/electronic-structure-evolution-pdco-nanocatalysts-under-oxidation-and-reduction-conditions02553nas a2200265 4500008004100000022001400041245009700055210006900152260000800221300001100229490000800240520168600248653002701934653002801961653000901989653000801998653002002006100001702026700002102043700001602064700002302080700002602103700003002129856012802159 2023 eng d a1385-894700aCo3O4 for sustainable CO2 reduction and possible fine-tuning towards selective CO production0 aCo3O4 for sustainable CO2 reduction and possible finetuning towa cSEP a1444590 v4713 a

Two main challenges involved in heterogeneous catalytic CO2 reduction are: (a) decreasing the consumption of H2 to the minimum required level with possibly the maximum CO2 conversion, and (b) concurrently enhancing the selectivity of the desired CO, at the cost of methane. Towards meeting these two challenges, Co3O4 spinel has been identified as a potential catalyst and it exhibits predominant CO selectivity > 673 K at atmospheric pressure. CO2 conversion begins > 523 K, with 100% CO selectivity observed > 673 K with CO2:H2 = 3:2. Current work shows a sustainable catalytic CO2 conversion to 100% CO selectivity with Co3O4-Nanocube (NC). Critically, CO selectivity and yield is observed to increase at the cost of methane with smaller amount of H2. 1:1 and 3:2 CO2:H2 ratio exhibits 88-100% CO selectivity with 24-32.5% CO2 conversion between 623 and 823 K. Irrespective of the input CO2:H2, ratio of CO2:H2 uptake changes from around 1:3 at 523 K to 1:1-1.5 at 823 K with concurrent production of significant methane to predominant CO, respectively. Surface electronic state changes was explored by near ambient pressure photoelectron spectroscopy, and the results suggests that Co3O4 is the active phase that promotes CO2 reduction selectively to CO. Broadening observed with the vibrational feature of the CO2 molecules at high temperature underscores the heterogeneous character of the catalyst surface, under operating conditions, due to changing electron density. By optimizing the gas hourly space velocity (GHSV), H2-lean CO2:H2 ratio, and the reaction temperature/pressure, 100% CO selectivity could be broadened to a range of operating conditions.

10aCarbon neutral economy10aheterogeneous catalysis10aRWGS10aSDG10aSurface Science1 aRanjan, Ravi1 aTekawadia, Jyoti1 aJain, Ruchi1 aMhamane, Nitin, B.1 aRaja, Thirumalaiswamy1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/co3o4-sustainable-co2-reduction-and-possible-fine-tuning-towards-selective-co-production