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Träfflista för sökning "LAR1:uu ;pers:(Ahuja Rajeev);pers:(Pathak Biswarup)"

Sökning: LAR1:uu > Ahuja Rajeev > Pathak Biswarup

  • Resultat 11-20 av 35
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11.
  • Li, Yunguo, et al. (författare)
  • Metal-decorated graphene oxide for ammonia adsorption
  • 2013
  • Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 103:2, s. 28007-
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on the first-principles density functional theory, we have studied the stability, electronic structure and ammonia storage capacity of metal-decorated graphene oxide (GO). Metal atoms (Mg and Li) are bonded strongly to the epoxy oxygen atoms on the surface of the GO sheet, which can act as high-surface-area adsorbent for the ammonia uptake and release. Each metal atom can bind several ammonia molecules around itself with a reasonable binding energy. We find metal-decorated GO can store up to tens of moles of ammonia per kilogram, which is far better than the recently reported excellent ammonia adsorption by GO.
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12.
  • Li, Yunguo, et al. (författare)
  • Strain-induced stabilization of Al functionalization in graphene oxide nanosheet for enhanced NH3 storage
  • 2013
  • Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 102:24, s. 243905-
  • Tidskriftsartikel (refereegranskat)abstract
    • Strain effects on the stabilization of Al ad-atom on graphene oxide (GO) nanosheet as well as its implications for NH3 storage have been investigated using first-principles calculations. Tensile strain is found to be very effective in stabilizing the Al ad-atom on GO. It strengthens the C-O bonds through an enhanced charge transfer from C to O atoms. Interestingly, Al's stability is governed by the bond strength of C-O rather than that of Al-O. Optimally strained Al-functionalized GO binds up to 6 NH3 molecules, while it binds no NH3 molecule in unstrained condition.
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13.
  • Liu, Peng, et al. (författare)
  • Anion-Anion Mediated Coupling in Layered Perovskite La2Ti2O7 for Visible Light Photocatalysis
  • 2013
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:27, s. 13845-13852
  • Tidskriftsartikel (refereegranskat)abstract
    • Anionic-anionic (N-N, P-P, N-P, and C-S) mediated coupling can be introduced in the layered perovskite La2Ti2O7 structure for visible light photocatalysis. The anionic-anionic codoped La2Ti2O7 systems lower the band gap much more than their respective monodoping systems. Moreover, the electronic band positions of the doped systems with respect to the water oxidation/reduction potentials show that codoped (N-N, N-P, and C-S) systems are more promising candidates for visible-light photocatalysis. The calculated defect formation energy shows that the codoped systems are more stable than their respective monodoped systems.
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14.
  • Liu, Peng, et al. (författare)
  • Cationic-anionic mediated charge compensation on La2Ti2O7 for visible light photocatalysis
  • 2013
  • Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:40, s. 17150-17157
  • Tidskriftsartikel (refereegranskat)abstract
    • The cationic-anionic mediated charge compensation effect was studied in the layered perovskite La2Ti2O7 for the visible light photocatalysis. Our screened hybrid density functional study shows that the electronic structure of La2Ti2O7 can be tuned by the cationic (V, Nb, Ta)/anionic (N) mono-and co-doping. Such mono-doping creates impurity states in the band gap which helps the electron-hole recombination. But if the charge compensation is made by the cationic-anionic mediated co-doping then such impurity states can be removed and can be a promising strategy for visible light photocatalysis. The absolute band edge position of the doped La2Ti2O7 has been aligned with respect to the water oxidation/reduction potential. The calculated defect formation energy shows the stability of the co-doping system is improved due to the coulomb interactions and charge compensations effect.
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15.
  • Liu, Peng, et al. (författare)
  • Hybrid density functional study on SrTiO3 for visible light photocatalysis
  • 2012
  • Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 37:16, s. 11611-11617
  • Tidskriftsartikel (refereegranskat)abstract
    • Hybrid Density Functional calculations have been performed on the electronic structure of anionic mono- (S, N, P, and C) and co-doped (N-N, N-P, N-S, P-P) SrTiO3 to improve their visible light photocatalytic activity. The electronic band position of doped system has been aligned with respect to the water oxidation/reduction potential. The electronic band position and optical absorption study shows that the mono- (S) and co-doped (N-N, N-P and P-P) SrTiO3 systems are promising materials for the visible-light photocatalysis. The calculated binding energies show that the co-doped systems are more stable than their respective mono-doped systems.
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16.
  • Liu, Peng, et al. (författare)
  • Layered Perovskite Sr2Ta2O7 for Visible Light Photocatalysis : A First Principles Study
  • 2013
  • Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:10, s. 5043-5050
  • Tidskriftsartikel (refereegranskat)abstract
    • The layered perovskite Sr2Ta2O7 has been investigated for efficient visible light photocatalysis using the first principles study. The electronic structure of Sr2Ta2O7 is tuned by the anionic (N)/cationic (Mo, W) mono- and co-doping. Such doping creates impurity states in the band gap and therefore reduces the band gap significantly. The absolute band edge position of the doped Sr2Ta2O7 with respect to the water oxidation/reduction potential depends a lot on the p/d-orbital's energies of anionic/cationic dopants, respectively. The stability of the co-doped system is governed by the Coulomb interactions and charge compensation effects.
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17.
  • Nair, Akhil S., et al. (författare)
  • Relativistic Effects in Platinum Nanocluster Catalysis : A Statistical Ensemble-Based Analysis
  • 2022
  • Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 126:8, s. 1345-1359
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanoclusters are materials of paramount catalytic importance. Among various unique properties featured by nanoclusters, a pronounced relativistic effect can be a decisive parameter in governing their catalytic activity. A concise study delineating the role of relativistic effects in nanocluster catalysis is carried by investigating the oxygen reduction reaction (ORR) activity of a Pt-7 subnanometer cluster. Global optimization analysis shows the critical role of spin-orbit coupling (SOC) in regulating the relative stability between structural isomers of the cluster. An overall improved ORR adsorption energetics and differently scaled adsorption-induced structural changes are identified with SOC compared to a non-SOC scenario. Ab initio atomistic thermodynamics analysis predicted nearly identical phase diagrams with significant structural differences for high coverage oxygenated clusters under realistic conditions. Though inclusion of SOC does not bring about drastic changes in the overall catalytic activity of the cluster, it is having a crucial role in governing the rate-determining step, transition-state configuration, and energetics of elementary reaction pathways. Furthermore, a statistical ensemble-based approach illustrates the strong contribution of low-energy local minimum structural isomers to the total ORR activity, which is significantly scaled up along the activity improving direction within the SOC framework. The study provides critical insights toward the importance of relativistic effects in determining various catalytic activity relevant features of nanoclusters.
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18.
  • Nair, Akhil S., et al. (författare)
  • Role of atomicity in the oxygen reduction reaction activity of platinum sub nanometer clusters : A global optimization study
  • 2021
  • Ingår i: Journal of Computational Chemistry. - : John Wiley & Sons. - 0192-8651 .- 1096-987X. ; 42:27, s. 1944-1958
  • Tidskriftsartikel (refereegranskat)abstract
    • Metal nanoclusters are an important class of materials for catalytic applications. Sub nanometer clusters are relatively less explored for their catalytic activity on account of undercoordinated surface structure. Taking this into account, we studied platinum-based sub nanometer clusters for their catalytic activity for oxygen reduction reaction (ORR). A comprehensive analysis with global optimization is carried out for structural prediction of the platinum clusters. The energetic and electronic properties of interactions of clusters with reaction intermediates are investigated. The role of structural sensitivity in the dynamics of clusters is unraveled, and unique intermediate specific interactions are identified. ORR energetics is examined, and exceptional activity for sub nanometer clusters are observed. An inverse size versus activity relationship is identified, challenging the conventional trends followed by larger nanoclusters. The principal role of atomicity in governing the catalytic activity of nanoclusters is illustrated. The structural norms governing the sub nanometer cluster activity are shown to be markedly different from larger nanoclusters.
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19.
  • Nair, Akhil S., et al. (författare)
  • Unraveling the single-atom electrocatalytic activity of transition metal-doped phosphorene
  • 2020
  • Ingår i: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 2:6, s. 2410-2421
  • Tidskriftsartikel (refereegranskat)abstract
    • The development of single-atom catalysts (SACs) for chemical reactions of vital importance in the renewable energy sector has emerged as an urgent priority. In this perspective, transition metal-based SACs with monolayer phosphorous (phosphorene) as the supporting material are scrutinized for their electrocatalytic activity towards the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) from first-principle calculations. The detailed screening study has confirmed a breaking of the scaling relationship between the ORR/OER intermediates, resulting in various activity trends across the transition metal series. Groups 9 and 10 transition metal-based SACs are identified as potential catalyst candidates with the platinum single atom offering bifunctional activity for OER and HER with diminished overpotentials. Ambient condition stability analysis of SACs confirmed a different extent of interaction towards oxygen and water compared to pristine phosphorene, suggesting room for improving the stability of phosphoreneviachemical functionalization.
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20.
  • Nisar, Jawad, et al. (författare)
  • Hole mediated coupling in Sr2Nb2O7 for visible light photocatalysis
  • 2012
  • Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 14:14, s. 4891-4897
  • Tidskriftsartikel (refereegranskat)abstract
    • The band gap reduction and effective utilization of visible solar light are possible by introducing the anionic hole-hole mediated coupling in Sr2Nb2O7. By using the first principles calculations, we have investigated the mono-and co-anionic doping (S, N and C) in layered perovskite Sr2Nb2O7 for the visible-light photocatalysis. Our electronic structure and optical absorption study shows that the mono- (N and S) and co-anionic doped (N-N and C-S) Sr2Nb2O7 systems are promising materials for the visible light photocatalysis. The calculated binding energies show that if the hole-hole mediated coupling could be introduced, the co-doped systems would be more stable than their respective mono-doped systems. Optical absorption curves indicate that doping S, (N-N) and (C-S) in Sr2Nb2O7 can harvest a longer wavelength of the visible light spectrum as compared to the pure Sr2Nb2O7 for efficient photocatalysis.
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  • Resultat 11-20 av 35

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