Electroreduction of molecular oxygen on preferentially oriented platinum electrodes in acid solution

Zinola, C.F.; Luna, A.M. Castro; Triaca, Walter Enrique; Arvía, Alejandro Jorge

doi:10.1007/bf00247782

Cited by 39 publications

(61 citation statements)

References 30 publications

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“…), in comparison with pure Pt [147][148][149][150][151][152] can be also interpreted in terms of increased Pt d-band vacancy (electronic factor) and its relative effect on the OH chemisorption from the electrolyte [153].…”

Section: Pt-based Catalysts and Non-noble Metal Electrocatalystsmentioning

confidence: 99%

Direct Methanol Fuel Cells: History, Status and Perspectives

Aricò

Baglio

Antonucci

2009

Electrocatalysis of Direct Methanol Fuel Cells

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Section: Pt-based Catalysts and Non-noble Metal Electrocatalystsmentioning

confidence: 99%

Direct Methanol Fuel Cells: History, Status and Perspectives

Aricò

Baglio

Antonucci

2009

Electrocatalysis of Direct Methanol Fuel Cells

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“…Thus, a lattice contraction due to alloying would result in a more favorable Pt-Pt distance for the dissociative adsorption of O 2 . Besides this, an interplay between electronic and geometric factors (Pt d-band vacancy and Pt-coordination numbers) and its relative effect on the OH chemisorption from the electrolyte occurs [12].…”

Section: Introductionmentioning

confidence: 99%

Electrocatalytic behaviour for oxygen reduction reaction of small nanostructured crystalline bimetallic Pt–M supported catalysts

et al. 2006

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A 60 wt% Pt-Fe/C and a 60 wt% Pt-Cu/C catalysts with Fe and Cu content of 5 wt% were prepared by using a combination of colloidal and incipient wetness methods; this has allowed synthesis of small nanostructured crystalline bimetallic catalysts with particle size less than 3 nm and with a suitable degree of alloying. These materials were studied in terms of structure, morphology and composition using XRD, XRF and TEM techniques. The electrocatalytic behaviour for ORR of the catalysts was investigated using the rotating disk technique and compared to that of a pure Pt catalyst with similar particle size. No improvement in performance was recorded with the Pt-Cu compared to Pt catalyst, whereas, a promoting effect in enhancing the ORR was observed for the Pt-Fe catalyst both with and without methanol in the oxygen-saturated electrolyte solution.

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“…[34][35][36][37] While these results are uncomplicated and somewhat expected, 49 other studies indicate that ORR at the Pt/ionomer interface may actually be more complex. Electrochemical impedance spectroscopy (EIS) studies of ORR at the Pt/Nafion interface at 100% relative humidity (RH) by Xie and Holdcroft 46 demonstrated that ORR involves potential-driven changes in transport characteristics of the bulk ionomer.…”

mentioning

confidence: 72%

Effects of Ionomer Morphology on Oxygen Reduction on Pt

Chlistunoff

Pivovar

2015

J. Electrochem. Soc.

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The oxygen reduction reaction (ORR) at the interface between platinum and Nafion 1100 equivalent weight was studied as a function of temperature (20-80 • C), humidity (10-100%), scan rate, the manner in which Nafion film was deposited, and the state of the Pt surface using ultramicroelectrodes employing cyclic voltammetry and chronoamperometry. ORR on smooth electrodes was strongly inhibited under specific conditions dependent on temperature, humidity, and scan rate. From the data presented, we postulate that dynamic changes in the molecular structure of the ionomer at the platinum interface result in differences in ORR voltammetry for films prepared and equilibrated under different conditions. The lack of similar changes for rough, platinized electrodes has been attributed to differences in initial ionomer structure and a higher energy barrier for ionomer restructuring. These model system studies yield insight into the ionomer-catalyst interface of particular interest for polymer electrolyte fuel cells. Sluggish oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs) is a bottleneck for the commercialization of PEFCs as automotive power sources. While replacing platinum as ORR catalyst in polymer electrolyte fuel cells (PEFCs) continues to be heavily pursued, 1,2 the metal, in spite of its high price, still remains the catalyst of choice for commercial applications. Because of that, much effort has been made to optimize cell performance with as little platinum as possible, i.e., to maximize the utilization of platinum. 3 Among various approaches to increase Pt utilization in PEFCs, the most promising are those simultaneously targeting multiple areas, where improvement is desired, e.g., Pt content in catalyst particles, strength of catalyst interaction with the support, particle agglomeration, etc. [4][5][6] However, the accessible surface area of Pt in actual catalyst layers is always smaller than expected from the mass loading and the catalyst particle size distribution due to the agglomeration, electronic isolation, and/or ionic isolation. [7][8][9][10] The ionic isolation may result from Pt particles not in contact with polymer electrolyte or Pt particles only in contact with the non-conducting regions of the polymer electrolyte. In either case, oxygen reduction reaction (ORR) cannot occur on such particles, as there is no mechanism for transporting protons to the reaction site. A few recent studies clearly demonstrate that the interfacial morphology of Nafion must play a central role in the ionic isolation of catalyst particles. Using electrochemical techniques, McGovern et al. 11 demonstrated that the surface of a nano-crystalline platinum catalyst is partially blocked by Nafion. A similar conclusion was reached by Ohma et al. 12 in case of smooth polycrystalline Pt surfaces. In other recent studies, 13,14 it was shown that the morphology of Nafion at smooth interfaces with gas is strongly affected by ionomer hydration and that ion conduction to the surface is very heterogenous on the...

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Electroreduction of molecular oxygen on preferentially oriented platinum electrodes in acid solution

Cited by 39 publications

References 30 publications

Direct Methanol Fuel Cells: History, Status and Perspectives

Direct Methanol Fuel Cells: History, Status and Perspectives

Electrocatalytic behaviour for oxygen reduction reaction of small nanostructured crystalline bimetallic Pt–M supported catalysts

Effects of Ionomer Morphology on Oxygen Reduction on Pt

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