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Studies on metal catalysts and carbo...

Zhang, Gaixia.

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Studies on metal catalysts and carbon materials for fuel cell applications.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Studies on metal catalysts and carbon materials for fuel cell applications./
Author:	Zhang, Gaixia.
Description:	198 p.
Notes:	Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1893.
Contained By:	Dissertation Abstracts International69-03B.
Subject:	Chemistry, Polymer. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR37139
ISBN:	9780494371398

Studies on metal catalysts and carbon materials for fuel cell applications.
Zhang, Gaixia.

Studies on metal catalysts and carbon materials for fuel cell applications. - 198 p.

Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1893.

Thesis (Ph.D.)--Ecole Polytechnique, Montreal (Canada), 2008.

As a potential candidate for an environmentally benign and highly efficient electric power generation technology, proton exchange membrane fuel cells (PEMFC) are now attracting great interest for various applications.

ISBN: 9780494371398Subjects--Topical Terms:

1018428
Chemistry, Polymer.

Studies on metal catalysts and carbon materials for fuel cell applications.
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005 20110519
008 110519s2008 ||||||||||||||||| ||eng d
020 $a 9780494371398
035 $a (UMI)AAINR37139
035 $a AAINR37139
040 $a UMI $c UMI
100 1 $a Zhang, Gaixia. $3 1266152
245 1 0 $a Studies on metal catalysts and carbon materials for fuel cell applications.
300 $a 198 p.
500 $a Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1893.
502 $a Thesis (Ph.D.)--Ecole Polytechnique, Montreal (Canada), 2008.
520 $a As a potential candidate for an environmentally benign and highly efficient electric power generation technology, proton exchange membrane fuel cells (PEMFC) are now attracting great interest for various applications.
520 $a The main objective of this project has been to investigate the interfacial interaction of Pt nanoparticles with their carbon supports, so as to determine ways to optimise the catalyst electrode and to increase its catalytic activity, thereby enhancing PEM fuel cell performance.
520 $a We first studied the interfacial interaction (leading to adhesion) of Pt nanoparticles evaporated onto untreated and Ar+-treated highly oriented pyrolytic graphite surfaces, with, respectively, low and high surface defect densities; HOPG was used as a model for carbon nanotubes (CNTs) and carbon fibers. We found that those Pt nanoparticles have very weak interactions with their pristine carbon material supports, with no evidence of compound formation between them. Our analysis, however, indicated that the adhesion of Pt nanoparticles to their supports can be enhanced, using ion beams, plasmas, or other treatments to establish defects on the carbon substrate surface. In addition, by using multicomponent XPS analysis with symmetric lineshapes for each Pt4f spectral component (4f7/2,5/2), we attributed the component peaks to the existence of (i) surface oxidation on the platinum nanoparticles, and different electronic configurations of (ii) surface and (iii) bulk Pt atoms.
520 $a One way of enhancing strong adhesion between them is by chemical functionalization of the support. Using mixed H2SO4/HNO3 acid treatments, we have characterized the surface chemistry of functionalized carbon fiber paper by combining infrared, Raman and X-ray photoelectron spectroscopies, to give new insights into the often-used oxidation of graphene-containing materials. We have, for the first time, demonstrated the presence of transient O-, N- and S-containing species during the oxidation process, as well as the fact that the intensities of those species varied unpredictably with treatment time, especially in the early stages, rather than constantly increasing with time.
520 $a Even with the functionalization of the CNTs to increase the mass activity of the catalyst, there is still a significant fraction of Pt that is isolated from the external circuit and/or the PEM, resulting in low Pt utilization. Growing CNTs directly on carbon fiber paper, followed by Pt deposition, however, ensures that all the Pt nanoparticles are in electrical contact with the external electrical circuit, improves Pt utilization and could potentially decrease Pt usage. In order to synthesize controlled, uniform CNTs, it is necessary to manage the size and density of the deposited CNT growth catalyst. We have studied Co nanoparticles and Co-Ni alloy nanoparticles, deposited onto carbon material supports. We found that these nanoparticles are quite reactive, not only with the carbon substrate but, also, with residual gas, even in ultra-high vacuum, to form surface carbides and oxides. This surface contaminant layer prevents further nanoparticle coalescence and helps to stabilize them. AFM shows that the surface layer helps to maintain nanoparticle dimensions that are essentially independent of the amount of Co/Ni deposited. By analyzing the Co/Ni nanoparticles, we also demonstrated that Co is more reactive than Ni.
520 $a In addition to enhancing the adhesion of the Pt nanoparticles to the carbon supports, the synthesis of specific platinum nanostructures has become an area of considerable interest, since catalytic efficiency and selectivity are highly dependent on the size and shape of the platinum material. Here, we have synthesized, for the first time, several novel nanostructures, such as 3D Pt nanoflowers and the single-crystalline Pt nanowire (NW)--CNT heterojunctions, via simple chemical reduction reactions, at room temperature, without templates or surfactants. Electrodes modified with these novel Pt nanostructures exhibit good electrocatalytic activities, which may ultimately lead to their adoption in PEM fuel cells. In addition, we were the first to demonstrate the direct growth of single-crystalline Pt nanowires on carbon materials. (Abstract shortened by UMI.)
590 $a School code: 1105.
650 4 $a Chemistry, Polymer. $3 1018428
650 4 $a Energy. $3 876794
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0495
690 $a 0791
690 $a 0794
710 2 $a Ecole Polytechnique, Montreal (Canada). $3 1018606
773 0 $t Dissertation Abstracts International $g 69-03B.
790 $a 1105
791 $a Ph.D.
792 $a 2008
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR37139