01371nas a2200205 4500008004100000022001400041245006700055210006700122260012500189300002300314490000700337520058300344100002600927700002300953700002000976700002500996700002201021700003001043856009201073 2007 eng d a0003-695100aEnergy analysis of field emitted electrons from a ZnO tetrapod0 aEnergy analysis of field emitted electrons from a ZnO tetrapod aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScAPR aArticle No. 1621020 v903 a

The experimental total energy distribution (TED) of the field emitted electrons from a single pod of a ZnO tetrapod has been obtained, exhibiting a two-peak feature. The energy difference between the two peaks in the TED is found to be nearly equal to the band gap of the bulk ZnO. The results show that field emitted electrons originate from both the conduction and valence bands. The peak position dependence on the applied voltage has also been observed. In the present case, the size of the ZnO tetrapod is not small enough to reflect the quantum confinement effects.

1 aAl-Tabbakh, Ahmed, A.1 aMore, Mahendra, A.1 aJoag, Dilip, S.1 aRamgir, Niranjan, S.1 aMulla, Imtiaz, S.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/energy-analysis-field-emitted-electrons-zno-tetrapod01922nas a2200205 4500008004100000022001400041245009300055210006900148260007300217300001400290490000800304520115100312653002101463653002201484653001401506653001501520100002801535700003001563856012301593 2008 eng d a0169-433200aEfficient route towards the covalent functionalization of single walled carbon nanotubes0 aEfficient route towards the covalent functionalization of single aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN a4936-49430 v2543 a

A simple and efficient method of chemical functionalization of both single and multiwalled carbon nanotubes has been discussed to give enhanced water solubility by rapidly and efficiently generating an appreciable amount of hydrophilic functional groups using microwave radiation. Surface functionalization containing more than 30 wt% of oxygen has been achieved, resulting into solubility of 2-5 mg/mL. Further covalent functionalization of such soluble SWNTs provides a remarkable degree of aniline functionalization through amidation, where the formation of polyaniline has been avoided. Functionalization of SWNTs is confirmed by techniques like electron microscopy, Fourier transform infrared spectroscopy, thermogravimetry, Raman spectroscopy, cyclic voltammetry and impedance spectroscopy. Electrochemical analysis suggests an enhanced double layer capacitance (similar to 110 F/g) of nanotubes after microwave treatment. Aniline functionalization of SWNTs shows possible variations on the nanotube topography with concomitant formation of a dynamic polymer layer on the nanotube surface. (C) 2008 Elsevier B.V. All rights reserved.

10aCarbon nanotubes10aFunctionalization10aMicrowave10asolubility1 aKakade, Bhalchandra, A.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/efficient-route-towards-covalent-functionalization-single-walled-carbon-nanotubes-002299nas a2200241 4500008004100000022001400041245011800055210006900173260009200242300001400334490000600348520130800354653002301662653004401685653005201729653001501781653003201796100002301828700002301851700002201874700003001896856013101926 2008 eng d a1533-488000aElectrochemical sensing of sulphur dioxide: a comparison using dodecanethiol and citrate capped gold nanoclusters0 aElectrochemical sensing of sulphur dioxide a comparison using do a26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USAbAMER SCIENTIFIC PUBLISHERScJUN a3184-31900 v83 a

A comparison of cyclic voltammograms of dodecanethiol (DDT) capped Au nanoclusters (5.0 +/- 0.5 nm) and trisodium citrate (Cit) capped Au nanoclusters (similar to 10-15 nm) modified glassy carbon electrode shows a dramatic variation in the current when exposed to a small amount of sulphur dioxide. This is explained using the electrocatalytic properties of Au nanoclusters towards the oxidation of SO2, thus facilitating the fabrication of electrochemical sensors for the detection of SO2. The intrinsic redox changes observed for gold nanocluster-modified glassy carbon electrodes disappear on passing SO2, despite a dramatic current increase, which indeed scales up with the amount of dissolved SO2. Interestingly, a complete rejuvenation of the redox behavior of gold is also observed on subsequent removal of SO2 from the solution by passing pure nitrogen for 15 minutes. Further, these nanoclusters when characterized with X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) after SO2 passage reveal a variety of SO2 adsorption modes on gold surface. XP spectra also show a shift of 1.03 eV towards higher binding energy indicating a strong adsorption of SO2 gas, while FTIR gives conclusive evidence for the interaction of SO2 with gold nanoparticles.

10acyclic voltammetry10aFourier transform infrared spectroscopy10amonolayer protected gold nanoclusters (Au-MPCs)10aSO2 sensor10aX-ray photoelectron spectra1 aSathe, Bhaskar, R.1 aRisbud, Mandar, S.1 aMulla, Imtiaz, S.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-sensing-sulphur-dioxide-comparison-using-dodecanethiol-and-citrate-capped-001441nas a2200217 4500008004100000022001400041245006600055210006600121260012500187300001100312490000700323520062500330100002300955700002800978700002201006700003001028700002401058700002301082700002001105856009801125 2008 eng d a0003-695100aEnhanced field emission from hexagonal rhodium nanostructures0 aEnhanced field emission from hexagonal rhodium nanostructures aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJUN a2531060 v923 a

Shape selective synthesis of nanostructured Rh hexagons has been demonstrated with the help of a modified chemical vapor deposition using rhodium acetate. An ultralow threshold field of 0.72 V/mu m is observed to generate a field emission current density of 4 x 10(-3) mu A/cm(2). The high enhancement factor (9325) indicates that the origin of electron emission is from nanostructured features. The smaller size of emitting area, excellent current density, and stability over a period of more than 3 h are promising characteristics for the development of electron sources. (C) 2008 American Institute of Physics.

1 aSathe, Bhaskar, R.1 aKakade, Bhalchandra, A.1 aMulla, Imtiaz, S.1 aPillai, Vijayamohanan, K.1 aLate, Dattatray, J.1 aMore, Mahendra, A.1 aJoag, Dilip, S. uhttps://library.ncl.res.in/content/enhanced-field-emission-hexagonal-rhodium-nanostructures-001411nas a2200181 4500008004100000022001400041245007600055210006900131260007300200300001200273490000800285520073500293100002301028700002201051700002201073700003001095856010401125 2010 eng d a0009-261400aEffect of Fe3O4 on morphology of Fe-SnO2 hyperbranched heterostructures0 aEffect of Fe3O4 on morphology of FeSnO2 hyperbranched heterostru aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN a121-1250 v4933 a

A simple modified thermal evaporation technique is employed for the synthesis of microstructured Fe:SnO2 system and their plausible growth mechanism has been proposed based on the results from various characterization techniques. Such structures grow in two steps; initially, growth of Fe core takes place from Fe3O4 source which acts as nucleating site for SnO2 growth on its surface as per the vapor-liquid- solid progression. Moreover, the composition of Fe/Sn source and temperature are found to have key roles in governing their morphology. XPS studies clearly demonstrate the presence of Fe species, which acts as a catalyst along with source for hetero-structure growth with SnO2. (C) 2010 Published by Elsevier B.V.

1 aSathe, Bhaskar, R.1 aWalke, Pravin, S.1 aMulla, Imtiaz, S.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/effect-fe3o4-morphology-fe-sno2-hyperbranched-heterostructures-001530nas a2200193 4500008004100000022001400041245012100055210006900176260007100245300001400316490000800330520075400338100002401092700002401116700001901140700002001159700003001179856012701209 2011 eng d a0002-786300aElectrochemical unzipping of multi-walled carbon nanotubes for facile synthesis of high-quality graphene nanoribbons0 aElectrochemical unzipping of multiwalled carbon nanotubes for fa a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a4168-41710 v1333 a

Here we report a remarkable transformation of carbon nanotubes (CNTs) to nanoribbons composed of a few layers of graphene by a two-step electrochemical approach. This consists of the oxidation of CNTs at controlled potential, followed by reduction to form graphene nanoribbons (GNRs) having smooth edges and fewer defects, as evidenced by multiple characterization techniques, including Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. This type of ``unzipping'' of CNTs (single-walled, multi-walled) in the presence of an interfacial electric field provides unique advantages with respect to the orientation of CNTs, which might make possible the production of GNRs with controlled widths and fewer defects.

1 aShinde, Dhanraj, B.1 aDebgupta, Joyashish1 aKushwaha, Ajay1 aAslam, Mohammed1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-unzipping-multi-walled-carbon-nanotubes-facile-synthesis-high-quality-002146nas a2200181 4500008004100000022001400041245014700055210006900202260011000271300001600381490000700397520133800404100002101742700001901763700002401782700003001806856012801836 2011 eng d a1463-907600aEnhanced electrocatalytic performance of functionalized carbon nanotube electrodes for oxygen reduction in proton exchange membrane fuel cells0 aEnhanced electrocatalytic performance of functionalized carbon n aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAPR a10312-103170 v133 a

Although nitrogen doped CNTs (N-CNTs) are considered as a promising alternative to platinized carbon for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs), the origin of the enhanced ORR activity with N-CNTs is not clear at present. Among several plausible reasons, the exposure of edge plane and creation of impurity band/surface states near the Fermi level are considered as major causes behind the catalytic activity. However, CNTs without nitrogen doping are not known to catalyze the ORR. In this work, we study the ORR activity of functionalized carbon nanotubes with different functional groups, such as sulfonic acid and phosphonic acid, in order to understand the role of surface functionalities in catalyzing the reaction. Functionalized CNTs show significantly enhanced activity towards the ORR, while CNTs without such surface functional groups do not reveal any such special ORR activity. Linear sweep voltammetry experiments with different rotation rates show diffusion controlled limiting current values for functionalized CNTs, and the `n' values derived from Koutecky-Levich plots are 3.3 and 1.7 for S-MWCNTs and P-MWCNTs, respectively. This work demonstrates the ORR activity of functionalized MWCNTs, which opens up new strategies for electrocatalyst design in PEMFCs.

1 aKannan, Ramaiyan1 aBipinlal, Unni1 aKurungot, Sreekumar1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/enhanced-electrocatalytic-performance-functionalized-carbon-nanotube-electrodes-oxygen-002211nas a2200169 4500008004100000022001400041245010500055210006900160260011000229300001400339490000600353520147900359100002301838700002101861700003001882856012901912 2011 eng d a1754-569200aEnhanced electrocatalytic performance of interconnected Rh nano-chains towards formic acid oxidation0 aEnhanced electrocatalytic performance of interconnected Rh nanoc aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAR a1029-10360 v43 a

A chain-like assembly of rhodium nanoparticles (5-7 nm mean diameter) has been synthesized from rhodium chloride with the help of polydentate molecules like tartaric and ascorbic acids (1 : 3 in mM scale) as capping agents at room temperature. Subsequent characterization using transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy reveals a unique inter-connected network like features, while their electrochemical behavior using cyclic voltammetry and current-time transient suggests potential applications as electrocatalysts in fuel cells. A significant negative shift in the onset potential as well as higher anodic peak current density for formic acid oxidation on Rh-tartaric acid (Rh-TA) as compared to that of bulk Rh metal confirms their higher electrocatalytic activity. Interestingly, the enhancement factor (R) with respect to that of bulk metallic Rh towards formic acid oxidation ranges up to 2000% for Rh-TA and 1200% for Rh-AA (Rh-ascorbic acid) respectively. The composition of Rh nano-chains has been further analyzed with thermogravimetry and Fourier transform infra-red spectroscopy to demonstrate the importance of controlling the chain topology using polyfunctional organic molecules. These findings open up new possibilities for tailoring nanostructured electrodes with potential benefits since the development of a better electrocatalysts for many fuel cell reactions continues to be an important challenge.

1 aSathe, Bhaskar, R.1 aBalan, Beena, K.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/enhanced-electrocatalytic-performance-interconnected-rh-nano-chains-towards-formic-acid-001098nas a2200193 4500008004100000022001400041245014500055210006900200260011000269300001400379490000700393520024500400100002400645700002500669700002600694700003000720700002400750856013000774 2011 eng d a1359-734500aEx-situ dispersion of core-shell nanoparticles of Cu-Pt on an in situ modified carbon surface and their enhanced electrocatalytic activities0 aExsitu dispersion of coreshell nanoparticles of CuPt on an in si aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcFEB a3951-39530 v473 a

Direct dispersion of core-shell nanoparticles on a carbon support (Cu@ Pt/C) has been achieved while retaining the essential core-shell features of the nanoparticles by adopting an in situ surface modification-cum-anchoring strategy.

1 aDhavale, Vishal, M.1 aUnni, SreeKuttan, M.1 aKagalwala, Husain, N.1 aPillai, Vijayamohanan, K.1 aKurungot, Sreekumar uhttps://library.ncl.res.in/content/ex-situ-dispersion-core-shell-nanoparticles-cu-pt-situ-modified-carbon-surface-and-their-001962nas a2200217 4500008004100000022001400041245010300055210006900158260007500227300001600302490000700318520113200325653003001457653001301487653001901500653002201519653001701541100002401558700003001582856013201612 2012 eng d a0947-653900aElectrochemical preparation of luminescent graphene quantum dots from multiwalled carbon nanotubes0 aElectrochemical preparation of luminescent graphene quantum dots aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcSEP a12522-125280 v183 a

Green luminescent, graphene quantum dots (GQDs) with a uniform size of 3, 5, and 8.2(+/- 0.3) nm in diameter were prepared electrochemically from MWCNTs in propylene carbonate by using LiClO4 at 90?degrees C, whereas similar particles of 23(+/- 2) nm were obtained at 30?degrees C under identical conditions. Both these sets of GQDs displayed a remarkable quantum efficiency of 6.3 and 5.1?%, respectively. This method offers a novel strategy to synthesise size-tunable GQDs as evidenced by multiple characterisation techniques like transmission and scanning electron microscopy, atomic force microscopy, Raman spectroscopy and X-ray diffraction (XRD). Photoluminescence of these GQDs can be tailored by size variation through a systematic change in key process parameters, like diameter of carbon nanotube, electric field, concentration of supporting electrolyte and temperature. GQDs are promising candidates for a variety of applications, such as biomarkers, nanoelectronic devices and chemosensors due to their unique features, like high photostability, biocompatibility, nontoxicity and tunable solubility in water.

10aelectrochemical synthesis10agraphene10aNanostructures10aphotoluminescence10aquantum dots1 aShinde, Dhanraj, B.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-preparation-luminescent-graphene-quantum-dots-multiwalled-carbon-nanotubes-000790nas a2200205 4500008004100000022001400041245008200055210006900137260007700206300001400283490000700297653002000304653003500324653001300359653001700372653002900389100002400418700003000442856011200472 2013 eng d a1433-785100aElectrochemical resolution of multiple redox events for graphene quantum dots0 aElectrochemical resolution of multiple redox events for graphene aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJAN a2482-24850 v5210acharging energy10adifferential pulse voltammetry10agraphene10aquantum dots10asingle-electron transfer1 aShinde, Dhanraj, B.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-resolution-multiple-redox-events-graphene-quantum-dots-002008nas a2200193 4500008004100000022001400041245013500055210006900190260011000259300001400369490000600383520117100389100002401560700002901584700002201613700002501635700003001660856012401690 2014 eng d a2040-336400aElectrochemical preparation of vertically aligned, hollow CdSe nanotubes and their p-n junction hybrids with electrodeposited Cu2O0 aElectrochemical preparation of vertically aligned hollow CdSe na aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG a9148-91560 v63 a

Vertically aligned, hollow nanotubes of CdSe are grown on fluorine doped tin oxide (FTO) coated glass substrates by ZnO nanowire template-assisted electrodeposition technique, followed by selective removal of the ZnO core using NH4OH. A detailed mechanism of nucleation and anisotropic growth kinetics of nanotubes have been studied by a combination of characterization tools such as chronoamperometry, SEM and TEM. Interestingly, ``as grown'' CdSe nanotubes (CdSe NTs) on FTO coated glass plates behave as n-type semiconductors exhibiting an excellent photo-response (with a generated photocurrent density value of similar to 470 mu A cm(-2)) white in contact with p-type Cu2O (p-type semiconductor, grown separately on FTO plates) because of the formation of a n-p heterojunction (type II). The observed photoresponse is 3 times higher than that of a similar device prepared with electrodeposited CdSe films (not nanotubes) and Cu2P on FTO. This has been attributed to the hollow 1-D nature of CdSe NTs, which provides enhanced inner and outer surface areas for better absorption of light and also assists faster transport of photogenerated charge carriers.

1 aDebgupta, Joyashish1 aDevarapalli, Rami, Reddy1 aRahman, Shakeelur1 aShelke, Manjusha, V.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-preparation-vertically-aligned-hollow-cdse-nanotubes-and-their-p-n-002323nas a2200241 4500008004100000022001400041245014400055210006900199260010200268300001200370490000700382520137800389653001501767653001101782653001101793653003001804653001401834100002401848700002401872700002401896700003001920856013101950 2015 eng d a0250-470700aElectrochemical preparation of nitrogen-doped graphene quantum dots and their size-dependent electrocatalytic activity for oxygen reduction0 aElectrochemical preparation of nitrogendoped graphene quantum do aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScAPR a435-4420 v383 a

Here we report a remarkable transformation of nitrogen-doped multiwalled carbon nanotubes (MWCNTs) to size selective nitrogen-doped graphene quantum dots (N-GQDs) by a two-step electrochemical method. The sizes of the N-GQDs strongly depend on the applied anodic potential, moreover increasing potential resulted in a smaller size of N-GQDs. These N-GQDs display many unusual size-dependant optoelectronic (blue emission) and electrocatalytic (oxygen reduction) properties. The presence of N dopants in the carbon framework not only causes faster unzipping of MWCNTs but also provides more low activation energy site for enhancing the electrocatalytic activity for technologically daunting reactions like oxygen reduction. The smaller size of N-GQDs has shown better performance as compared to the large N-GQDs. Interestingly, N-GQDs-3 (size = 2.5 +/- 0.3 nm, onset potential = 0.75 V) show a 30-mV higher positive onset potential shift compared to that of N-GQDs-2 (size = 4.7 +/- 0.3 nm, onset potential = 0.72 V) and 70 mV than that of N-GQDs-1 (size = 7.2 +/- 0.3, onset potential = 0.68 V) for oxygen reduction reaction (ORR) in a liquid phase. These result in the size-dependent electrocatalytic activity of N-GQDs for ORR as illustrated by the smaller sized N-GQDs (2.5 +/- 0.3 nm) undoubtedly promising metal-free electrocatalysts for fuel cell applications.

10afuel cells10aMWCNTs10aN-GQDs10aoxygen reduction reaction10aunzipping1 aShinde, Dhanraj, B.1 aDhavale, Vishal, M.1 aKurungot, Sreekumar1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/electrochemical-preparation-nitrogen-doped-graphene-quantum-dots-and-their-size-dependent-002394nas a2200181 4500008004100000022001400041245014400055210006900199260011000268300001400378490000600392520159400398100002101992700002402013700002402037700003002061856012102091 2016 eng d a2046-206900aEnhanced nucleation of polypropylene by metal-organic frameworks (MOFs) based on aluminium dicarboxylates: influence of structural features0 aEnhanced nucleation of polypropylene by metalorganic frameworks  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcDEC a1907-19120 v63 a

Metal-organic frameworks (MOFs) based on aluminium dicarboxylates provide a new platform for the enhanced nucleation of isotactic polypropylene (iPP). For instance, aluminium dicarboxylates exhibit a unique butterfly-like structure similar to that of carboxylate-alumoxanes and correlates well with the nucleation characteristics of iPP. A subtle change in the structure of the ligand backbone (fumarate/succinate) does not alter the framework structure despite changing the hydrophilic/hydrophobic character and its subsequent nucleation characteristics. This suggests that the nucleating agent should facilitate favourable interaction with hydrophobic iPP for efficient nucleation. Further, a systematic variation of the alkyl chain length in the Al-dicarboxylate does not change the nucleation efficiency considerably, even though it increases the distance between the octahedral alumina chains in the metal-organic framework, suggesting that the butterfly-like structure present in the framework is a key aspect for nucleation. Finally, the significance of the orientational conformation of the dicarboxylate around the metal centre for the nucleation is confirmed by the poor nucleation efficiency of chromium and zirconium suberate MOFs where the orientation of suberate would be different from that of aluminium suberate due to the difference in the ligation of the carboxylate group. The present work thus provides valuable pathways for developing new nucleating agents based on MOFs with appropriate selection and orientation of the organic linkers around the metal centre.

1 aMani, Mohan, Raj1 aChellaswamy, Ramesh1 aMarathe, Yogesh, N.1 aPillai, Vijayamohanan, K. uhttps://library.ncl.res.in/content/enhanced-nucleation-polypropylene-metal-organic-frameworks-mofs-based-aluminium-0