C. N. R. Rao

Jawaharlal Nehru Centre for Advanced Scientific Research, Bengalūru, Karnātaka, India

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Publications (801)2507.85 Total impact

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    ABSTRACT: Performance of supercapacitors based on 1:1 (by weight) composites of polyaniline (PANI) with nanosheets of nitrogenated reduced graphene oxide (NRGO), BC1.5N, MoS2 and WS2 has been investigated in detail. The highest specific capacitance is found with the 1:1 NRGO-PANI composite, the value being 561 F/g at a current density of 0.2 A/g. All the 1:1 nanocomposites show good cyclability. Increasing the PANI content increases the specific capacitance and the highest value found being 715 F/g at a current density of 0.5 A/g in the case of the 1:6 NRGO-PANI composite. However, all the 1:6 composites show a marked decrease in specific capacitance with increase in current density. The energy density of 1:6 NRGO-PANI is ~25 Wh/Kg at 0.5 A/g and 1:1 NRGO-PANI is ~19 Wh/Kg at 0.2 A/g. NRGO-PANI composites clearly stand out as viable materials for practical applications.
    Nano Energy 03/2015; 12. · 10.21 Impact Factor
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    ABSTRACT: Performance of supercapacitors based on 1:1 (by weight) composites of polyaniline (PANI) with nanosheets of nitrogenated reduced graphene oxide (NRGO), BC 1.5 N, MoS 2 and WS 2 has been investigated in detail. The highest specific capacitance is found with the 1:1 NRGO-PANI composite, the value being 561 F/g at a current density of 0.2 A/g. All the 1:1 nanocomposites show good cyclability. Increasing the PANI content increases the specific capacitance and the highest value found being 715 F/g at a current density of 0.5 A/g in the case of the 1:6 NRGO-PANI composite. However, all the 1:6 composites show a marked decrease in specific capacitance with increase in current density. The energy density of 1:6 NRGO-PANI is $ 25 Wh/Kg at 0.5 A/g and 1:1 NRGO-PANI is $ 19 Wh/Kg at 0.2 A/g. NRGO-PANI composites clearly stand out as viable materials for practical applications.
    Nano Energy 12/2014; online. · 10.21 Impact Factor
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    Nano Energy 12/2014; online. · 10.21 Impact Factor
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    ABSTRACT: MoS2 nanosheets have emerged to be exciting materials with unusual properties of great interest, some with potential applications.
    Chemical Physics Letters 08/2014; 609:172–183. · 1.99 Impact Factor
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    ABSTRACT: Noting that BiI3 and the well-known topological insulator (TI) Bi2Se3 have the same high symmetry parent structures, and that it is desirable to find a wide-band gap TI, we determine here the effects of pressure on the structure, phonons and electronic properties of rhombohedral BiI3. We report a pressure-induced insulator-metal transition near 1.5 GPa, using high pressure electrical resistivity and Raman measurements. X-ray diffraction studies, as a function of pressure, reveal a structural peculiarity of the BiI3 crystal, with a drastic drop in c/a ratio at 1.5 GPa, and a structural phase transition from rhombohedral to monoclinic structure at 8.8 GPa. Interestingly, the metallic phase, at relatively low pressures, exhibits minimal resistivity at low temperatures, similar to that in Bi2Se3. We corroborate these findings with first-principles calculations and suggest that the drop in the resistivity of BiI3 in the 1–3 GPa range of pressure arises possibly from the appearance of an intermediate crystal phase with a lower band-gap and hexagonal crystal structure. Calculated Born effective charges reveal the presence of metallic states in the structural vicinity of rhombohedral BiI3. Changes in the topology of the electronic bands of BiI3 with pressure, and a sharp decrease in the c/a ratio below 2 GPa, are shown to give rise to changes in the slope of phonon frequencies near that pressure.
    Journal of Physics Condensed Matter 06/2014; 26(27):275502. · 2.22 Impact Factor
  • S. R. Lingampalli, C. N. R. Rao
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    ABSTRACT: The performance of ZnO/Pt/Cd1-yZnyS (y= 0.0, 0.2) heterostructures in generating hydrogen on visible light irradiation is substantially improved if ZnO is co-substituted 10 with N and F, since such anion substitution results in intense visible light absorption and decrease in the band gap.
    Journal of Materials Chemistry A: Materials for Energy and Sustainability 04/2014;
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    ABSTRACT: Homogeneous graphene-MOF composites based on a 2D pillared-bilayer MOF (Cd-PBM), {[Cd4(azpy)2(pyrdc)4(H2O)2]·9H2O}n (azpy = 4,4'-azopyridine, pyrdc = pyridine-2,3-dicarboxylate), have been synthesized, using both graphene oxide (GO) and benzoic acid functionalized graphene (BFG). The composites GO@Cd-PBM and BFG@Cd-PBM demonstrate growth of the 2D nano-sheets of MOF on the graphene surface. While the pristine MOF, Cd-PBM shows selective CO2 uptake with a single-step type-I adsorption profile, the composites show stepwise CO2 uptake with a large hysteresis. With H2O and MeOH, on the other hand, the composites show a single-step adsorption unlike the parent MOF.
    Dalton Transactions 03/2014; · 4.10 Impact Factor
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    ABSTRACT: The present study demonstrates the use of few-layer borocarbonitride nanosheets synthesized by a simple method as non-platinum cathode catalysts for the oxygen reduction reaction (ORR) in alkaline medium. Composition-dependent ORR activity is observed and the best performance was found when the composition was carbon-rich. Mechanistic aspects reveal that ORR follows the 4 e(-) pathway with kinetic parameters comparable to those of the commercial Pt/C catalyst. Excellent methanol tolerance is observed with the BCN nanosheets unlike with Pt/C.
    Chemistry - An Asian Journal 01/2014; · 4.57 Impact Factor
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    ABSTRACT: It is no exaggeration to state that the energy crisis is the most serious challenge that we face today. Among the strategies to gain access to reliable, renewable energy, the use of solar energy has clearly emerged as the most viable option. A promising direction in this context is artificial photosynthesis. In this article, we briefly describe the essential features of artificial photosynthesis in comparison with natural photosynthesis and point out the modest success that we have had in splitting water to produce oxygen and hydrogen, specially the latter.
    Current science 01/2014; 106(4):518-527. · 0.83 Impact Factor
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    ABSTRACT: We report the design and synthesis of two porous graphene frameworks (PGFs) prepared via covalent functionalization of reduced graphene oxide (RGO) with iodobenzene followed by a C-C coupling reaction. In contrast to RGO, these 3D frameworks show high surface area (BET, 825 m(2) g(-1)) and pore volumes due to the effect of pillaring. Interestingly, both the frameworks show high CO2 uptake (112 wt% for PGF-1 and 60 wt% for PGF-2 at 195 K up to 1 atm). PGFs show nearly 1.2 wt% H2 storage capacity at 77 K and 1 atm, increasing to ∼1.9 wt% at high pressure. These all carbon-based porous solids based on pillared graphene frameworks suggest the possibility of designing related several such novel materials with attractive properties.
    Chemical Communications 01/2014; · 6.38 Impact Factor
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    ABSTRACT: Nitrogen-doped reduced graphene oxide (RGO) samples with different nitrogen content, prepared by two different methods, as well as nitrogen-doped few-layer graphene have been investigated as supercapacitor electrodes. Two electrode measurements have been carried out both in aqueous (6M KOH) and in ionic liquid media. Nitrogen-doped reduced graphene oxides exhibit satisfactory specific capacitance, the values reaching 126F/g at a scan rate of 10mV/s in aqueous medium. Besides providing supercapacitor characteristics, the study has shown the nitrogen content and surface area to be important factors. High surface-area borocarbonitrides, BxCyNz, prepared by the urea route appear to be excellent supercapacitor electrode materials. Thus, BC4.5N exhibits a specific capacitance of 169F/g at a scan rate of 10mV/s in aqueous medium. In an ionic liquid medium, nitrogen-doped RGO and BC4.5N exhibit specific capacitance values of 258F/g and 240F/g at a scan rate of 5mV/s. The ionic liquid enables a larger operating voltage range of 0.0-2.5V compared to 0.0-1V in aqueous medium.
    Solid State Communications 12/2013; · 1.70 Impact Factor
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    ABSTRACT: Two sorts of MoS2 : A single-layer, metallic form of MoS2 (1T-MoS2 ) and a nanocomposite of a second form of MoS2 (few-layer 2H-MoS2 ) with heavily nitrogenated reduced graphene oxide (NRGO; N content ca. 15 %) show outstanding performance in the production of H2 under visible-light illumination.
    Angewandte Chemie International Edition 11/2013; · 11.34 Impact Factor
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    ABSTRACT: Single-walled nanohorns (SWNHs) have been prepared by sub-merged arc discharge of graphite electrodes in liquid nitrogen. The samples were examined by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Nitrogen and boron doped SWNHs have been prepared by the sub-merged arc discharge method using melamine and elemental boron as precursors. Intensification of Raman D-band and stiffening of G-band has been observed in the doped samples. The electrical resistance of the SWNHs varies in opposite directions with nitrogen and boron doping. Functionalization of SWNHs through amidation has been carried out for solubilizing them in non-polar solvents. Water-soluble SWNHs have been produced by acid treatment and non-covalent functionalization with a coronene salt. SWNHs have been decorated with nanoparticles of Au, Ag and Pt. Interaction of electron donor (tetrathiafulvalene, TTF) and acceptor molecules (tetracyanoethylene, TCNE) with SWNHs has been investigated by Raman spectroscopy. Progressive softening and stiffening of Raman G-band has been observed respectively with increase in the concentration of TTF and TCNE.
    Journal of Cluster Science 10/2013; xxx:xxx-xxx. · 1.11 Impact Factor
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    ABSTRACT: Exposure of few-layer MoS2, WS2 and MoSe2 to high-temperature shock waves causes morphological changes and a significant decrease in the interlayer separation between the (0 0 2) planes, the decrease being greatest in MoSe2. Raman spectra show softening of both the A1g and the E2g1 modes initially, followed by a slightly stiffening. Using first-principles density functional theoretical analysis of the response of few-layer MoS2 to shock waves, we propose that a combination of shear and uniaxial compressive deformation leads to flattening of MoS2 sheets which is responsible for the changes in the vibrational spectra.
    Chemical Physics Letters 07/2013; 582:105. · 1.99 Impact Factor
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    ABSTRACT: Prompted by the early results on the catalytic activity of LiMn2O4 and related oxides in the photochemical oxidation of water, our detailed study of several manganese oxides has shown that trivalency of Mn is an important factor in determining the catalytic activity. Thus, Mn2O3, LaMnO3, and MgMn2O4 are found to be very good catalysts with turnover frequencies of 5 × 10(-4) s(-1), 4.8 × 10(-4) s(-1), and 0.8 ×10(-4) s(-1), respectively. Among the cobalt oxides, Li2Co2O4 and LaCoO3-especially the latter-exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10(-4) s(-1) and 1.4 × 10(-3) s(-1), respectively. The common feature among the catalytic Mn and Co oxides is not only that Mn and Co are in the trivalent state, but Co(3+) in the Co oxides is in the intermediate t2g(5)eg(1) state whereas Mn(3+) is in the t2g(3)eg(1) state. The presence of the eg(1) electron in these Mn and Co oxides is considered to play a crucial role in the photocatalytic properties of the oxides.
    Proceedings of the National Academy of Sciences 07/2013; · 9.81 Impact Factor
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    ABSTRACT: Two kinds in a box: The electronic and optical properties of ZnO substituted with nitrogen and fluorine are studied both experimentally and theoretically. The presence of fluorine enhances the incorporation of nitrogen in the lattice. Co-substitution reduces the optical band gap of ZnO significantly and increases the dielectric constant. The long-wavelength visible absorption of N, F-ZnO is reflected in its bright orange color.
    ChemPhysChem 06/2013; · 3.36 Impact Factor
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    ABSTRACT: Nanoparticles of CdO2 and ZnO2 are shown to oxidize toluene primarily to benzaldehyde in the 160-180 °C range, around which temperature the nanoparticles decompose to give the oxides. The product selectivity and other features of the reaction are explained taking into account the various by products formed in the reaction. These metal peroxides also activate the C-H bonds of cyclohexane. It is possible to bring down the reaction temperature by partially substituting Zn in ZnO2 by Ni.
    ChemPlusChem 06/2013; 78:837-842. · 3.24 Impact Factor
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    ABSTRACT: Heavily nitrogenated graphene oxide containing 18 wt% nitrogen, prepared by microwave synthesis with urea as the nitrogen source, shows outstanding performance as a supercapacitor electrode material, with the specific capacitance going up to 461 F g−1.
    J. Mater. Chem. A. 06/2013; 1(26):7563-7565.
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    ABSTRACT: Ionothermal synthesis: Ultrathin (~4 nm) few-layer nanostructures of Bi2 Se3 and related chalcogenides have been prepared by green ionothermal synthesis. The ionic liquid acts as an intercalating and stabilizing agent in addition to being an efficient solvent for the synthesis of few-layer Bi2 Se3 . High electrical conductivity and minimal thermal conductivity optimize the thermoelectric properties of few-layer Bi2 Se3 .
    Chemistry - A European Journal 05/2013; · 5.93 Impact Factor
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    ABSTRACT: With the objective of investigating the direct conversion of inorganic carbonates such as CaCO3 to hydrocarbons, assisted by transition metal ions, we have carried out studies on CaCO3 in an intimate admixture with iron oxides (FeCaCO) with a wide range of Fe/Ca mole ratios (x), prepared by co-precipitation. The hydrogen reduction of FeCaCO at 673 K gives up to 23% yield of the hydrocarbons CH4, C2H4, C2H6 and C3H8, leaving solid iron residues in the form of iron metal, oxides and carbide particles. The yield of hydrocarbons increases with x and the conversion of hydrocarbons occurs through the formation of CO. While the total yield of hydrocarbons obtained by us is comparable to that in the Fischer–Tropsch synthesis, the selectivity for C2–C3 hydrocarbons reported here is noteworthy.
    RSC Advances 04/2013; 3(20):7224-7229. · 3.71 Impact Factor

Publication Stats

13k Citations
2,507.85 Total Impact Points

Institutions

  • 1992–2014
    • Jawaharlal Nehru Centre for Advanced Scientific Research
      • • Chemistry and Physics of Materials Unit
      • • International Centre for Materials Science (ICMS)
      • • New Chemistry Unit
      Bengalūru, Karnātaka, India
  • 1992–2011
    • Bhabha Atomic Research Centre
      • Chemistry Division
      Mumbai, Mahārāshtra, India
  • 2010
    • National Institute for Materials Science
      • International Center for Materials Nanoarchitectonics (MANA)
      Tsukuba, Ibaraki-ken, Japan
  • 2006–2010
    • University of California, Santa Barbara
      • Materials Research Laboratory
      Santa Barbara, California, United States
  • 1977–2010
    • Indian Institute of Science
      • Department of Solid State and Structural Chemistry Unit
      Bengalore, State of Karnataka, India
  • 2008
    • Uppsala University
      • Department of Engineering Sciences
      Uppsala, Uppsala, Sweden
    • Mahatma Gandhi University
      • School of Chemical Sciences
      Kottayam, Kerala, India
  • 2007
    • Bielefeld University
      Bielefeld, North Rhine-Westphalia, Germany
  • 1984–2007
    • University of Cambridge
      • • Department of Materials Science and Metallurgy
      • • Faculty of Physics and Chemistry
      Cambridge, ENG, United Kingdom
  • 2004
    • Weizmann Institute of Science
      • Department of Materials and Interfaces
      Israel
  • 2000
    • National Physical Laboratory - India
      Old Delhi, NCT, India
  • 1997
    • Raman Research Institute
      Bengalūru, Karnātaka, India
  • 1996
    • The Royal Institution of Great Britain
      Londinium, England, United Kingdom
  • 1995
    • University of Wales
      Cardiff, Wales, United Kingdom
  • 1993
    • Paul Sabatier University - Toulouse III
      • Centre Inter-universitaire de Recherche et d'Ingénierie en Matériaux (CIRIMAT)
      Toulouse, Midi-Pyrenees, France
  • 1980–1987
    • Tata Institute of Fundamental Research
      • Department of Condensed Matter Physics and Materials Science
      Mumbai, Mahārāshtra, India
  • 1979
    • La Trobe University
      Melbourne, Victoria, Australia
  • 1966–1977
    • Indian Institute of Technology Kanpur
      • Department of Chemistry
      Kānpur, Uttar Pradesh, India
  • 1975–1976
    • University of Oxford
      • Inorganic Chemistry Laboratory
      Oxford, ENG, United Kingdom
  • 1968–1971
    • Purdue University
      • Department of Chemistry
      West Lafayette, IN, United States