02488nas a2200265   4500008004100000022001400041245020700055210006900262260007300331300001200404490000800416520142000424653002101844653003601865653002101901653001701922653002401939653002601963653002901989653001402018653001202032100002702044700001902071856013202090       2009                        eng d  a1387-181100aDependence of Si-29 NMR chemical shielding properties of precursor silicate species, Q(0) on its local structure at the pre-nucleation stages of zeolite synthesis - a DFT based computational correlation0 aDependence of Si29 NMR chemical shielding properties of precurso  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN  a105-1130 v1223 a<p>The exploration for new zeolite structures with tailored framework architectures for enhanced catalytic applications requires the knowledge about their nucleation and crystallization at molecular level. Nuclear magnetic resonance (NMR) is one of the most widely tried techniques to understand this. However, by NMR, it is difficult to accurately assign the molecular level precursor silicate structures at the pre-nucleation stages of zeolite synthesis. Hence, understanding the chemical shielding of such precursor molecules using quantum mechanical (QM) computations is extremely useful. Alkali is a fundamental component in the alkali based hydrothermal zeolite synthesis and its nature plays a major role. In the present report, we attempt to understand the differences in the local structure of the primary building block such as Si(OH)(4) (Q(0) silicate species) due to the associated alkali and their influence on NMR chemical shielding properties. Present work reports the calculation of Si-29 NMIR isotropic chemical shifts of T species with different cations such as Na, K and Ca using density functional theory (DFT). Results of natural bonding orbital (NBO) analysis, Perturbation theory energy analysis and electron density iso-surfaces were employed to obtain a deeper insight about their influence on the chemical shielding and on zeolite synthesis. (C) 2009 Elsevier Inc. All rights reserved.</p>10aAb initio method10aDensity Functional Theory (DFT)10aElectron density10aNBO analysis10aPerturbation theory10aQ(0) silicate species10aSi-29 NMR chemical shift10asynthesis10azeolite1 aSelvaraj, Kaliaperumal1 aKurian, Reshmi  uhttps://library.ncl.res.in/content/dependence-si-29-nmr-chemical-shielding-properties-precursor-silicate-species-q0-its-local-002052nas a2200265   4500008004100000022001400041245015000055210006900205260000900274300001400283490000700297520102600304653002401330653003601354653005501390653003801445653003001483653002001513100002501533700002501558700002401583700002701607700002601634856012601660       2024                        eng d  a0360-319900aComputational identification of most potent atom pair catalysts for electrocatalytic nitrogen reduction reaction over hydrogen evolution reaction0 aComputational identification of most potent atom pair catalysts   cMAR   a1345-13580 v583 a<p>
	Robust electrocatalytic atom pair compositions (APCs) where Nitrogen Reduction Reaction (NRR) is more enhanced over competing Hydrogen Evolution Reaction (HER) is searched for using computational studies based on Density Functional Theory based methods. Atomic pairs are anchored on mechanically and thermally stable graphene surfaces. A wide range of transition metal based atom pair compositions from 3d, 4d, and 5d groups are systematically investigated for reduction of dinitrogen molecule with lower reduction barrier as compared to HER. APR compositions of Ni-Rh with an overall limiting potential of -0.22 V, Fe-W with an overall limiting potential of -0.26 V and Co-Pt with an overall limiting potential of -0.28 V are identified as the most potent atomic pairs for enhanced nitrogen reduction reaction over the HER. Finally, the performance of most potent composition, viz., Ni-Rh is validated to be consistent with respect to their thermodynamic stability and performance within the solvent effects.</p>
10aAtom pair catalysts10aDensity Functional Theory (DFT)10aElectrochemical nitrogen reduction reaction (eNRR)10ahydrogen evolution reaction (HER)10aIR stretching frequencies10aN-N bond length1 aVerma, Tushar, Singh1 aDar, Afshana, Hassan1 aDar, Manzoor, Ahmad1 aSelvaraj, Kaliaperumal1 aKrishnamurty, Sailaja  uhttps://library.ncl.res.in/content/computational-identification-most-potent-atom-pair-catalysts-electrocatalytic-nitrogen