02517nas a2200145 4500008004100000245013200041210006900173260000900242300001600251490000600267520191800273100002402191700002602215856013002241 2019 eng d00aMolecular and dissociative adsorption of oxygen on au-pd bimetallic clusters: role of composition and spin state of the cluster0 aMolecular and dissociative adsorption of oxygen on aupd bimetall cJULY a12687-126950 v43 a

Utilization of molecular oxygen as an oxidizing agent in industrially important reactions is the ultimate goal to design environmentally benign processes under ambient conditions. However, the high thermal stability and a large O-O dissociation barrier in O-2 molecule pose a great challenge toward its successful application in the oxidative chemistry. To achieve this goal, different catalysts based on monometallic and bimetallic clusters have been developed over the years to promote binding and dissociation of molecular oxygen. The successful design of efficient metal cluster catalysis needs an in-depth knowledge of synergistic effects between different metal atoms and intrinsic catalytic mechanisms for O-2 adsorption and dissociation. Here, we present a systematic theoretical investigation of reaction pathways for O-2 adsorption and dissociation on Au-8, Pd-8, and Au8-nPdn (n = 1-7) nanoclusters in different spin states. The density functional calculations point out that the O-2 dissociation barriers can be significantly reduced with the help of certain bimetallic clusters along specific spin channels. Our results particularly indicate that Au5Pd3 and Au1Pd7 show very large O-2 binding energies of 1.76 and 1.69 eV, respectively. The enhanced O-2 binding subsequently leads to low activation barriers of 0.98 and 1.19 eV along the doublet and quartet spin channels, respectively, without the involvement of any spin flip-over for O-2 dissociation. Furthermore, the computed O-2 dissociation barriers are significantly low as compared to the already reported barriers (1.95-3.65 eV) on monometallic and bimetallic Au-Ag clusters. The results provide key mechanistic insights into the interaction and dissociation of molecular oxygen with Au-Pd clusters, which can prove informative for the design of efficient catalysts for oxidative chemistry involving molecular oxygen as a reactant.

1 aDar, Manzoor, Ahmad1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/molecular-and-dissociative-adsorption-oxygen-au-pd-bimetallic-clusters-role-composition-and02877nas a2200277 4500008004100000022001400041245014900055210006900204260000800273300001600281490000600297520188700303653003702190653001702227653000802244653002302252653001302275653002002288653003002308100002502338700002202363700002902385700002602414700002902440856013002469 2021 eng d a2168-048500aMechanistic investigations on the catalytic transfer hydrogenation of lignin-derived monomers over Ru catalysts: theoretical and kinetic studies0 aMechanistic investigations on the catalytic transfer hydrogenati cOCT a14040-140500 v93 aThe hydrodeoxygenation (HDO) reaction of oxygenated compounds such as lignin-derived phenolics is well studied using molecular H-2 as a hydrogen source, yet the use of high pressures discourages its use on an industrial scale. As an alternative, the catalytic transfer hydrogenation (CTH) pathway provides in situ hydrogenation species, which reduces the need for the high-pressure infrastructure required when molecular hydrogen is used. Nevertheless, this strategy is scantly studied, and in lieu with this, herein we report the kinetic and mechanistic investigations of the CTH strategy for the HDO of guaiacol, phenol, anisole veratrole, and eugenol to their respective products. For potential commercialization purposes, low loading of metal, milder reaction conditions, and high selectivity toward desired products with a high H/C ratio were considered while designing catalysts (0.5 wt % Ru on SiO2-Al2O3, SiO2, Al2O3-acidic, Al2O3-basic, and Al2O3-neutral) for these reactions. As high as 74% cyclohexanol yield from guaiacol was achieved at 225 degrees C in the presence of isopropyl alcohol (IPA) as the hydrogen source and over the Ru/Al2O3-acidic catalyst reduced at 150 degrees C. A detailed kinetic study is carried out to understand the interaction of the substrate and intermediates with the catalyst and the influence of reaction parameters on the product formation. It was observed that the cisisomer of 2-methoxycyclohexanol rapidly undergoes further conversion than the trans-isomer. The experimental observations are substantiated through density functional theory (DFT) studies on Ru(0001) and guaiacol molecule complexes. DFT studies indicate that the adsorption of the cis-isomer is more exothermic as compared to that of the trans counterpart, and the underlying electronic factors are elucidated using charge density difference and density of states plots.10acatalytic transfer hydrogenation10aCyclohexanol10aDFT10aHydrodeoxygenation10akinetics10alignin monomers10aSupported metal catalysts1 aKhan, Tufeil, Sartaj1 aSingh, Dheerendra1 aSamal, Pragnya, Paramita1 aKrishnamurty, Sailaja1 aDhepe, Paresh, Laxmikant uhttp://library.ncl.res.in/content/mechanistic-investigations-catalytic-transfer-hydrogenation-lignin-derived-monomers-over-ru01581nas a2200193 4500008004100000022001400041245013600055210006900191260000900260300001400269490000600283520085800289100002101147700003001168700001601198700002201214700002601236856012501262 2022 eng d a2470-134300aMapping the finite-temperature behavior of conformations to their potential energy barriers: case studies on Si6B and Si5B clusters0 aMapping the finitetemperature behavior of conformations to their cFEB  a6167-61730 v73 a

Dynamical simulations of molecules and materials have been the route to understand the rearrangement of atoms within them at different temperatures. Born-Oppenheimer molecular dynamical simulations have further helped to comprehend the reaction dynamics at various finite temperatures. We take a case study of Si6B and Si5B clusters and demonstrate that their finite-temperature behavior is rather mapped to the potential energy surface. The study further brings forth the fact that an accurate description of the dynamics is rather coupled with the accuracy of the method in defining the potential energy surface. A more precise potential energy surface generated through the coupled cluster method is finally used to identify the most accurate description of the potential energy surface and the interconnected finite-temperature behavior.

1 aManeri, Asma, H.1 aSingh, Chandrodai, Pratap1 aKumar, Ravi1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/mapping-finite-temperature-behavior-conformations-their-potential-energy-barriers-case02479nas a2200325 4500008004100000245010800041210006900149260000800218300001400226490000600240520139800246653001601644653002401660653002601684653002301710653001501733653001701748100002101765700002601786700002901812700002901841700002501870700002601895700002101921700002201942700001601964700002601980700002602006856012102032 2023 eng d00aMnXWO4 nanostructure-based catalysts for single-step oxidation of cyclohexane and methane to oxygenates0 aMnXWO4 nanostructurebased catalysts for singlestep oxidation of  cAPR a7245-72580 v63 a

Activation of the C-H bond in cyclohexane (CYH) and methane is a crucial step to obtain desirable oxygenated products using nanostructured catalyst and is a great challenge and an efficient route to mitigate the inauspicious effects of climate change. The active sites were identified using XRD, HR-TEM, SEM, N2 sorption analysis, TPR, Raman, XPS, TGA, in situ DRIFT, XAS, etc. In optimal reaction conditions, 46% of CYH was converted into adipic acid (AA) on MnxWO4 nanostructures within 6 h. The recyclability test confirmed the catalyst heterogeneity, which revealed no appreciable loss of catalytic activity even after three consecutive reactions. In situ DRIFT study reveals that CYH is oxidized to cyclohexanone and cyclohexanol (KA oil) and is further oxidized to AA via carboxylate intermediates. DFT studies disclosed that MnOx species are responsible for the C-H activation of CYH, and the Mn2+/Mn3+ redox centers play a vital role in the absorption of KA oil to form AA. Herein, we demonstrated the significant role of the ``MnOx'' species and that adequate Lewis and Bronsted acidic sites, redox centers of (Mn2+/Mn3+), and lattice oxygen are accountable for the CYH conversion toward the AA. Additionally, we have reported the oxidation of methane to methanol (146 mu mole per gram of catalyst) in the presence of water at 75 degrees C without over-oxidation products.

10aAdipic Acid10aC-H bond activation10aCyclohexane oxidation10amethane activation10aMnOx chain10aRedox center1 aPrabu, Marimuthu1 aManikandan, Marimuthu1 aSamal, Pragnya, Paramita1 aGurrala, Lakshmi, Prasad1 aMekala, Siva, Prasad1 aArchana, Ramakrishnan1 aNayak, Chandrani1 aBhattacharyya, D.1 aJha, S., N.1 aKrishnamurty, Sailaja1 aRaja, Thirumalaiswamy uhttp://library.ncl.res.in/content/mnxwo4-nanostructure-based-catalysts-single-step-oxidation-cyclohexane-and-methane00811nas a2200217 4500008004100000022001400041245011200055210006900167260000800236490000700244653001900251653001900270653001800289653004200307653001100349100002700360700003000387700002600417700002500443856012500468 2024 eng d a2192-650600aMetal-organic frameworks for enhanced hydrogen generation from syngas: a density functional theory approach0 aMetalorganic frameworks for enhanced hydrogen generation from sy cNOV0 v8910acarbon capture10aH-2 separation10aMetal organic10aPorous coordination network (PCN-250)10aSyngas1 aGopalsamy, Karuppasamy1 aSingh, Chandrodai, Pratap1 aKrishnamurty, Sailaja1 aBabaRao, Ravichandar uhttp://library.ncl.res.in/content/metal-organic-frameworks-enhanced-hydrogen-generation-syngas-density-functional-theory01993nas a2200229 4500008004100000022001400041245010000055210006900155260000800224300001100232490000800243520116600251653001701417653003601434653003201470653004401502653002401546100002501570700001801595700002601613856012401639 2025 eng d a0016-236100aMimicking characteristics of cast iron for enhanced electrocatalytic dehydrogenation of methane0 aMimicking characteristics of cast iron for enhanced electrocatal cFEB a1336740 v3813 a

Enhancing the efficiency of methane dehydrogenation through chemical modification of electrocatalytic iron surfaces with impurities that resemble cast iron properties is demonstrated computationally using Density Functional Theory methodologies. Investigating methane dehydrogenation on thermally stable Fe surfaces with discrete planes and anchoring impurities such as Al, C, and Si minimized reduction barriers. Electrochemical treatment of methane on these robust surfaces yields clean hydrogen and carbon-based compounds, such as carbon nanomaterials and carbon black. As for the most efficient active sites for enhanced methane dehydrogenation, the active plane 100 with 5.5 % C impurities and 0.51 eV reduction barrier is determined to be the most dependable, followed by the active plane 110 with 5.5 % Si impurities and the lower 0.98 eV reduction barrier. Utilizing CI-NEB (Nudged Elastic Band), the dissociation barrier investigation established the electrolytic catalysts' performance. This work paves the way for experimentalists and demonstrates the economic viability of Fe-based catalysts for the Catalytic Dehydrogenation of Methane.

10acarbon black10aDensity Functional Theory (DFT)10aDry methane reforming (DMR)10aElectrochemical methane dehydrogenation10aFe surface catalyst1 aVerma, Tushar, Singh1 aDevi, Nandini1 aKrishnamurty, Sailaja uhttp://library.ncl.res.in/content/mimicking-characteristics-cast-iron-enhanced-electrocatalytic-dehydrogenation-methane