03338nas a2200253 4500008004100000022001400041245019100055210006900246260010600315300001400421490000700435520231200442653003202754653001002786653003002796653001702826653001002843100002402853700002502877700001902902700002202921700002402943856011702967 2010 eng d a0013-468600aPt-MoOx-carbon nanotube redox couple based electrocatalyst as a potential partner with polybenzimidazole membrane for high temperature polymer electrolyte membrane fuel cell applications0 aPtMoOxcarbon nanotube redox couple based electrocatalyst as a po aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR a2878-28870 v553 a

A redox couple based electrocatalyst comprising of Pt-Multi Wall Carbon NanoTube (Pt-MWCNT) promoted with molybdenum oxide (MoOx, 2 < x < 3) nanoparticles was prepared. The objective was to effectively organize the Pt-MoOx interface on the smooth MWCNT surface to overcome the practical difficulties associated with establishing such interface with Pt dispersed on carbon morphologies possessing surface irregularities. The present study revealed the importance of stringent controlling of the additive level for maintaining a balanced bifunctional behavior of the catalyst combination through the synergistic effects by the components and the need of a proton conducting membrane operable at high temperature to get better output from the Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems. An indigenously developed polybenzimidazole (PBI) membrane was used to fabricate a membrane electrode assembly (MEA) as it can be operated at higher temperatures compared to that of Nafion membranes. MoOx additive level was carefully controlled by monitoring the active Pt area by cyclic voltammetry. All prepared electrocatalysts were characterized by using HRTEM, XRD and XPS to get information on dispersion and morphology, crystalinity and oxidation state of different elements, respectively. The system prepared with 5% MoOx addition with respect to Pt (hereafter Pt-MoOx(5%)-MWCNT) displayed balanced active Pt area and excellent oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) activities. Rotating Disk Electrode (ROE) system was extensively utilized to understand the ORR kinetics and the favorable role of MoOx as the promoter in the reaction. The kinetic current (j(k)) measured at 0.02 V vs. Hg/Hg2SO4 electrode from the Koutecky-Levich plots was 9 times higher and the apparent activation energy during single cell evaluation was 27 kJ/mol lower for the MoOx promoted system, compared to the system without the additive. A higher operating temperature significantly favored the cell performance by a combined effect of enhancement in proton conductivity of the PBI membrane and possible kinetic benefit by the well postulated oxygen spill over effect by the MoOx type systems in some combinations involving such systems. (C) 2010 Elsevier Ltd. All rights reserved.

10aMethanol oxidation reaction10aMWCNT10aoxygen reduction reaction10aPBI membrane10aPEMFC1 aVellacheri, Ranjith1 aUnni, SreeKuttan, M.1 aNahire, Sandip1 aKharul, Ulhas, K.1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/pt-moox-carbon-nanotube-redox-couple-based-electrocatalyst-potential-partner-001247nas a2200229 4500008004100000022001400041245008600055210006900141260007100210300001400281490000700295520042100302653001900723653001400742653003000756653002400786100002400810700002500834700002400859700001800883856011600901 2012 eng d a0897-475600aDisordered brownmillerite Ba2InCeO5+delta with enhanced oxygen reduction activity0 aDisordered brownmillerite Ba2InCeO5delta with enhanced oxygen re a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL a2823-28280 v243 a

A disordered brownmillerite, Ba2InCeO5+delta, with slight tetragonal distortion from ideal cubic perovskite is synthesized and its oxygen reduction reactivity tested. The material displayed oxygen reduction behavior in alkaline solution comparable to that of standard 40 wt % Pt/C catalyst and attractive activity characteristics which renders it a potential system for low temperature fuel cell applications.

10abrownmillerite10afuel cell10aoxygen reduction reaction10aRietveld refinement1 aJijil, Chamundi, P.1 aUnni, SreeKuttan, M.1 aSreekumar, Kurungot1 aDevi, Nandini uhttp://library.ncl.res.in/content/disordered-brownmillerite-ba2inceo5delta-enhanced-oxygen-reduction-activity-002385nas a2200253 4500008004100000022001400041245008400055210006900139260007100208300001600279490000600295520147900301653002101780653002001801653002001821653001401841653003001855100002501885700002701910700002801937700002701965700002401992856011502016 2015 eng d a1944-824400aCarbon nanohorn-derived graphene nanotubes as a platinum-free fuel cell cathode0 aCarbon nanohornderived graphene nanotubes as a platinumfree fuel a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV a24256-242640 v73 a

Current low-temperature fuel cell research mainly focuses on the development of efficient nonprecious electrocatalysts for the reduction of dioxygen molecule due to the reasons like exorbitant cost and scarcity of the current state-of-the-art Pt-based catalysts. As a potential alternative to such costly electrocatalysts, we report here the preparation of an efficient graphene nanotube based oxygen reduction electrocatalyst which has been derived from single walled nanohorns, comprising a thin layer of graphene nanotubes and encapsulated iron oxide nanopartides (FeGNT). FeGNT shows a surface area of 750 m(2)/g, which is the highest ever reported among the metal encapsulated nanotubes. Moreover, the graphene protected iron oxide nanoparticles assist the system to attain efficient distribution of Fe-N-x and quaternary nitrogen based active reaction centers, which provides better activity and stability toward the oxygen reduction reaction (ORR) in acidic as well as alkaline conditions. Single cell performance of a proton exchange membrane fuel cell by using FeGNT as the cathode catalyst delivered a maximum power density of 200 mW cm(-2) with Nafion as the proton exchange membrane at 60 degrees C. The facile synthesis strategy with iron oxide encapsulated graphitic carbon morphology opens up a new horizon of hope toward developing Pt-free fuel cells and metal-air batteries along with its applicability in other energy conversion and storage devices.

10acarbon nanohorns10acarbon nanotube10aelectrocatalyst10afuel cell10aoxygen reduction reaction1 aUnni, SreeKuttan, M.1 aIllathvalappil, Rajith1 aBhange, Siddheshwar, N.1 aPuthenpediakkal, Hasna1 aKurungot, Sreekumar uhttp://library.ncl.res.in/content/carbon-nanohorn-derived-graphene-nanotubes-platinum-free-fuel-cell-cathode-001961nas a2200241 4500008004100000022001400041245013300055210006900188260007500257300001400332490000600346520103800352653002101390653001801411653001501429653003001444653001301474100002501487700002901512700002401541700002601565856012801591 2015 eng d a2196-021600aCoSe2 supported on nitrogen-doped carbon nanohorns as a methanol-tolerant cathode for air-breathing microlaminar flow fuel cells0 aCoSe2 supported on nitrogendoped carbon nanohorns as a methanolt aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcSEP a1339-13450 v23 a

The synthesis of CoSe2 nanoparticles supported on nitrogendoped carbon nanohorns (CoSe2/NCNH) and the influence of the interaction of the metal centre with the NCNH on the oxygen reduction reaction (ORR) are reported. CoSe2/NCNH shows a 50 mV lower onset overpotential and a 150 mV positive shift in the half-wave potential compared to CoSe2 supported on carbon and carbon nanohorns. This suggests that the intrinsic activity and the density of active reaction centres of CoSe2 are modified by NCNHs. An air-breathing direct meth-anol microlaminar flow fuel cell (mLFFC) is constructed using CoSe2/NCNH as a methanol-tolerant cathode catalyst. A maximum power density of 10.05 mWcm(-2) and a maximum current density of 124.20 mAcm(-2) are achieved with CoSe2/NCNH compared to the non-doped catalyst, CoSe2/C and Pt/C with 5m methanol as the fuel. The improved activity of CoSe2/ NCNH is attributed to the peculiar morphology and the nitrogen doping of the carbon nanohorns. This catalyst could be a suitable alternative to Pt.

10acarbon nanohorns10achalcogenides10afuel cells10aoxygen reduction reaction10aplatinum1 aUnni, SreeKuttan, M.1 aMora-Hernandez, Juan, M.1 aKurungot, Sreekumar1 aAlonso-Vante, Nicolas uhttp://library.ncl.res.in/content/cose2-supported-nitrogen-doped-carbon-nanohorns-methanol-tolerant-cathode-air-breathing-0