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<p>A redox couple based electrocatalyst comprising of Pt-Multi Wall Carbon NanoTube (Pt-MWCNT) promoted with molybdenum oxide (MoOx, 2 &lt; x &lt; 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.</p>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-002096nas a2200217   4500008004100000022001400041245014300055210006900198260000800267490000700275520126500282653002301547653001701570653003101587653002101618653003201639100002501671700002701696700003101723856012401754       2024                        eng d  a1615-684600aEstablishing a new efficiency descriptor for methanol oxidation reaction and its validation with commercially available Pt-based catalysts0 aEstablishing a new efficiency descriptor for methanol oxidation   cJUN0 v243 a<p>Direct methanol fuel cells (DMFCs) have received a lot of attention in recent years as promising technology for generating clean and efficient energy. In DMFC, the anode catalyst is a vital component because it is involved in the oxidation of methanol, which produces electrons that can be used as an energy source. Cyclic voltammetry (CV) is commonly used to test the characteristics of the electrode materials before they are employed in the actual fuel cell. Interestingly in the case of DMFCs CV also is a useful technique to obtain vital information about the performance and expected efficiency of the electrodes. In general, the CV of methanol electrooxidation for Pt-based catalysts has two peaks, If in the forward scan (anodic scan) and Ib in the backward scan (cathodic scan). The ratio of these two peaks (If/Ib) is the most commonly used criterion for investigating CO poisoning in catalysts. However, there is a great deal of ambiguity surrounding this criterion, owing to the genesis of Ib. Addressing this we present here a new criterion to evaluate the efficiency of the catalyst using the same CV technique. We validate this newly proposed criterion with commercial Pt/C (comm. Pt/C) and other commercially available alloy catalysts.</p>
10acatalyst poisoning10aCO tolerance10adirect methanol fuel cells10aelectrocatalysis10aMethanol oxidation reaction1 aDeshpande, Pooja, S.1 aRadhakrishnan, Thulasi1 aPrasad, Bhagavatula, L. V.  uhttp://library.ncl.res.in/content/establishing-new-efficiency-descriptor-methanol-oxidation-reaction-and-its-validation